U.S. patent application number 17/319260 was filed with the patent office on 2021-09-09 for light-emitting device and electronic device.
The applicant listed for this patent is Semiconductor Energy Laboratory Co., Ltd.. Invention is credited to Akio ENDO, Masaaki HIROKI.
Application Number | 20210280807 17/319260 |
Document ID | / |
Family ID | 1000005608688 |
Filed Date | 2021-09-09 |
United States Patent
Application |
20210280807 |
Kind Code |
A1 |
HIROKI; Masaaki ; et
al. |
September 9, 2021 |
LIGHT-EMITTING DEVICE AND ELECTRONIC DEVICE
Abstract
A highly portable and highly browsable light-emitting device is
provided. A light-emitting device that is less likely to be broken
is provided. The light-emitting device has a strip-like region
having high flexibility and a strip-like region having low
flexibility that are arranged alternately. In the region having
high flexibility, a light-emitting panel and a plurality of spacers
overlap with each other. In the region having low flexibility, the
light-emitting panel and a support overlap with each other. When
the region having high flexibility is bent, the angle between
normals of facing planes of the two adjacent spacers changes
according to the bending of the light-emitting panel; thus, a
neutral plane can be formed in the light-emitting panel or in the
vicinity of the light-emitting panel.
Inventors: |
HIROKI; Masaaki; (Isehara,
JP) ; ENDO; Akio; (Atsugi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Semiconductor Energy Laboratory Co., Ltd. |
Atsugi-shi |
|
JP |
|
|
Family ID: |
1000005608688 |
Appl. No.: |
17/319260 |
Filed: |
May 13, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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17095943 |
Nov 12, 2020 |
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17319260 |
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16248890 |
Jan 16, 2019 |
10840464 |
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17095943 |
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15807670 |
Nov 9, 2017 |
10199585 |
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16248890 |
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14921059 |
Oct 23, 2015 |
9818961 |
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15807670 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 51/0097 20130101;
Y02E 10/549 20130101; H01L 2251/5338 20130101 |
International
Class: |
H01L 51/00 20060101
H01L051/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 28, 2014 |
JP |
2014-219135 |
Claims
1. A light-emitting device comprising: a light-emitting panel
including a light-emitting element, wherein the light-emitting
device is configured to be folded in two parts such that a
light-emitting surface of the light-emitting panel faces inward,
wherein the light-emitting panel includes a light-emitting region
and a non-light-emitting region surrounding the light-emitting
region, wherein the non-light-emitting region includes a driver
circuit, and wherein the light-emitting device includes a
light-blocking layer provided to overlap the non-light-emitting
region.
2. A light-emitting device comprising: a light-emitting panel
including a light-emitting element, wherein the light-emitting
device is configured to be folded in two parts such that a
light-emitting surface of the light-emitting panel faces inward,
wherein the light-emitting panel includes a light-emitting region
and a non-light-emitting region surrounding the light-emitting
region, wherein the non-light-emitting region includes a driver
circuit, and wherein the light-emitting device includes a
light-blocking layer provided to overlap the non-light-emitting
region which is located in a region folded in the two parts.
3. A light-emitting device comprising: a light-emitting panel
including a light-emitting element, wherein the light-emitting
device is configured to be folded in two parts such that a
light-emitting surface of the light-emitting panel faces inward,
wherein the light-emitting panel includes a light-emitting region
and a non-light-emitting region surrounding the light-emitting
region, wherein the non-light-emitting region includes a driver
circuit, wherein the light-emitting device includes a
light-blocking layer provided to overlap the non-light-emitting
region, and wherein the light-blocking layer includes an opening in
a portion overlapping with the light-emitting region.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 17/095,943, filed Nov. 12, 2020, now pending, which is a
continuation of U.S. application Ser. No. 16/248,890, filed Jan.
16, 2019, now U.S. Pat. No. 10,840,464, which is a continuation of
U.S. application Ser. No. 15/807,670, filed Nov. 9, 2017, now U.S.
Pat. No. 10,199,585, which is a continuation of U.S. application
Ser. No. 14/921,059, filed Oct. 23, 2015, now U.S. Pat. No.
9,818,961, which claims the benefit of a foreign priority
application filed in Japan as Serial No. 2014-219135 on Oct. 28,
2014, all of which are incorporated by reference.
TECHNICAL FIELD
[0002] One embodiment of the present invention relates to a
light-emitting device. In particular, one embodiment of the present
invention relates to a light-emitting device utilizing organic
electroluminescence (hereinafter also referred to as EL).
[0003] Note that one embodiment of the present invention is not
limited to the above technical field. Examples of the technical
field of one embodiment of the present invention include a
semiconductor device, a display device, a light-emitting device, a
power storage device, a memory device, an electronic device, a
lighting device, an input device (e.g., a touch sensor), an
input/output device (e.g., a touch panel), a driving method
thereof, and a manufacturing method thereof.
BACKGROUND ART
[0004] Recent light-emitting devices and display devices are
expected to be applied to a variety of uses and become
diversified.
[0005] For example, light-emitting devices and display devices for
mobile devices and the like are required to be thin, lightweight,
and less likely to be broken.
[0006] Light-emitting elements utilizing EL (also referred to as EL
elements) have features such as ease of thinning and lightening,
high-speed response to input signal, and driving with a
direct-current low voltage source; therefore, application of the
light-emitting elements to light-emitting devices and display
devices has been proposed.
[0007] For example, Patent Document 1 discloses a flexible active
matrix light-emitting device in which an organic EL element and a
transistor serving as a switching element are provided over a film
substrate.
REFERENCE
Patent Document
[0008] [Patent Document 1] Japanese Published Patent Application
No. 2003-174153
DISCLOSURE OF INVENTION
[0009] For application to mobile devices, the size of a
light-emitting device or display device has been reduced so that
the device can be highly portable. On the other hand, a larger
light-emitting region or display region has been required so that
the device can be highly browsable.
[0010] An object of one embodiment of the present invention is to
provide a highly portable light-emitting device, display device,
input/output device, electronic device, or lighting device. Another
object of one embodiment of the present invention is to provide a
highly browsable light-emitting device, display device,
input/output device, or electronic device. Another object of one
embodiment of the present invention is to provide a highly portable
and highly browsable light-emitting device, display device,
input/output device, or electronic device.
[0011] Another object of one embodiment of the present invention is
to provide a novel light-emitting device, display device,
input/output device, electronic device, or lighting device. Another
object of one embodiment of the present invention is to provide a
light-emitting device, display device, input/output device,
electronic device, or lighting device that is less likely to be
broken. Another object of one embodiment of the present invention
is to provide a highly reliable light-emitting device, display
device, input/output device, electronic device, or lighting device.
Another object of one embodiment of the present invention is to
provide a light-emitting device, display device, input/output
device, electronic device, or lighting device with low power
consumption.
[0012] Another object of one embodiment of the present invention is
to provide a lightweight light-emitting device or the like. Another
object of one embodiment of the present invention is to provide a
thin light-emitting device or the like. Another object of one
embodiment of the present invention is to provide a flexible
light-emitting device or the like. Another object of one embodiment
of the present invention is to provide a light-emitting device or
lighting device with a seamless large light-emitting region or a
display device, input/output device, or electronic device with a
seamless large display region.
[0013] Note that the descriptions of these objects do not disturb
the existence of other objects. In one embodiment of the present
invention, there is no need to achieve all the objects. Other
objects can be derived from the description of the specification,
the drawings, and the claims.
[0014] One embodiment of the present invention is a light-emitting
device including a first region, a second region, and a third
region. The first region is positioned between the second region
and the third region. The first region has higher flexibility than
the second region and the third region. The first region includes a
light-emitting panel and a plurality of spacers. The second region
includes the light-emitting panel and a first support. The third
region includes the light-emitting panel and a second support. The
light-emitting panel has higher flexibility than the first support
and the second support. The first region includes a portion where
each of the plurality of spacers and the light-emitting panel
overlap with each other. The second region includes a portion where
the first support and the light-emitting panel overlap with each
other. The third region includes a portion where the second support
and the light-emitting panel overlap with each other. When the
first region is bent, the angle between normals of facing planes of
the two adjacent spacers changes according to the bending of the
light-emitting panel.
[0015] Another embodiment of the present invention is a
light-emitting device including a first region, a second region,
and a third region. The first region is positioned between the
second region and the third region. The first region has higher
flexibility than the second region and the third region. The first
region includes a light-emitting panel and a plurality of spacers.
The second region includes the light-emitting panel and a first
support. The third region includes the light-emitting panel and a
second support. The light-emitting panel has higher flexibility
than the first support and the second support. The first region
includes a portion where each of the plurality of spacers and the
light-emitting panel overlap with each other. The second region
includes a portion where the first support and the light-emitting
panel overlap with each other. The third region includes a portion
where the second support and the light-emitting panel overlap with
each other. The plurality of spacers each include a portion fixed
to the light-emitting panel.
[0016] Another embodiment of the present invention is a
light-emitting device including a first region, a second region,
and a third region. The first region is positioned between the
second region and the third region. The first region has higher
flexibility than the second region and the third region. The first
region includes a light-emitting panel, a protective layer, and a
plurality of spacers. The second region includes the light-emitting
panel, the protective layer, and a first support. The third region
includes the light-emitting panel, the protective layer, and a
second support. The light-emitting panel has higher flexibility
than the first support and the second support. The protective layer
has higher flexibility than the first support and the second
support. The first region includes a portion where each of the
plurality of spacers and the light-emitting panel overlap with each
other with the protective layer positioned therebetween. The second
region includes a portion where the first support and the
light-emitting panel overlap with each other with the protective
layer positioned therebetween. The third region includes a portion
where the second support and the light-emitting panel overlap with
each other with the protective layer positioned therebetween. The
plurality of spacers each include a portion fixed to the protective
layer.
[0017] In one embodiment of the present invention, the number of
the spacers is two or more. For example, one embodiment of the
present invention is a light-emitting device including a first
region, a second region, and a third region. The first region is
positioned between the second region and the third region. The
first region has higher flexibility than the second region and the
third region. The first region includes a light-emitting panel, a
first spacer, and a second spacer. The second region includes the
light-emitting panel and a first support. The third region includes
the light-emitting panel and a second support. The light-emitting
panel has higher flexibility than the first support and the second
support. The first region includes a portion where the first spacer
and the light-emitting panel overlap with each other. The first
region includes a portion where the second spacer and the
light-emitting panel overlap with each other. The second region
includes a portion where the first support and the light-emitting
panel overlap with each other. The third region includes a portion
where the second support and the light-emitting panel overlap with
each other. When the first region is bent, the angle between
normals of facing planes of the first spacer and the second spacer
changes according to the bending of the light-emitting panel.
[0018] Another embodiment of the present invention is a
light-emitting device including a first region, a second region,
and a third region. The first region is positioned between the
second region and the third region. The first region has higher
flexibility than the second region and the third region. The first
region includes a light-emitting panel, a first spacer, and a
second spacer. The second region includes the light-emitting panel
and a first support. The third region includes the light-emitting
panel and a second support. The light-emitting panel has higher
flexibility than the first support and the second support. The
first region includes a portion where the first spacer and the
light-emitting panel overlap with each other. The first region
includes a portion where the second spacer and the light-emitting
panel overlap with each other. The second region includes a portion
where the first support and the light-emitting panel overlap with
each other. The third region includes a portion where the second
support and the light-emitting panel overlap with each other. The
first spacer includes a portion fixed to the light-emitting panel.
The second spacer includes a portion fixed to the light-emitting
panel.
[0019] Another embodiment of the present invention is a
light-emitting device including a first region, a second region,
and a third region. The first region is positioned between the
second region and the third region. The first region has higher
flexibility than the second region and the third region. The first
region includes a light-emitting panel, a protective layer, a first
spacer, and a second spacer. The second region includes the
light-emitting panel, the protective layer, and a first support.
The third region includes the light-emitting panel, the protective
layer, and a second support. The light-emitting panel has higher
flexibility than the first support and the second support. The
protective layer has higher flexibility than the first support and
the second support. The first region includes a portion where the
first spacer and the light-emitting panel overlap with each other
with the protective layer positioned therebetween. The first region
includes a portion where the second spacer and the light-emitting
panel overlap with each other with the protective layer positioned
therebetween. The second region includes a portion where the first
support and the light-emitting panel overlap with each other with
the protective layer positioned therebetween. The third region
includes a portion where the second support and the light-emitting
panel overlap with each other with the protective layer positioned
therebetween. The first spacer includes a portion fixed to the
protective layer. The second spacer includes a portion fixed to the
protective layer.
[0020] In the above structure, the protective layer preferably
includes a portion fixed to the light-emitting panel. In
particular, in the first region, the protective layer preferably
includes a portion fixed to the light-emitting panel.
[0021] Another embodiment of the present invention is a
light-emitting device including a first region, a second region,
and a third region. The first region is positioned between the
second region and the third region. The first region has higher
flexibility than the second region and the third region. The first
region includes a light-emitting panel and a connection portion.
The second region includes the light-emitting panel and a first
support. The third region includes the light-emitting panel and a
second support. The light-emitting panel has higher flexibility
than the first support and the second support. The first region
includes a portion where the connection portion and the
light-emitting panel overlap with each other. The second region
includes a portion where the first support and the light-emitting
panel overlap with each other. The third region includes a portion
where the second support and the light-emitting panel overlap with
each other. The connection portion includes an elastic body and a
plurality of spacers. The elastic body is configured to connect the
first support and the second support. The plurality of spacers each
include an opening. The plurality of spacers are connected to each
other through the elastic body in the openings.
[0022] Another embodiment of the present invention is a
light-emitting device including a first region, a second region,
and a third region. The first region is positioned between the
second region and the third region. The first region has higher
flexibility than the second region and the third region. The first
region includes a light-emitting panel and a connection portion.
The second region includes the light-emitting panel and a first
support. The third region includes the light-emitting panel and a
second support. The light-emitting panel has higher flexibility
than the first support and the second support. The first region
includes a portion where the connection portion and the
light-emitting panel overlap with each other. The second region
includes a portion where the first support and the light-emitting
panel overlap with each other. The third region includes a portion
where the second support and the light-emitting panel overlap with
each other. The connection portion is configured to connect the
first support and the second support. The connection portion
includes an elastic body, a first spacer, and a second spacer. The
first spacer includes an opening. The second spacer includes an
opening. The first spacer and the second spacer are connected to
each other through the elastic body in the openings.
[0023] In the above structure, the plurality of spacers each
preferably include a portion fixed to the light-emitting panel.
[0024] In any of the above structures, the elastic body is
preferably a spring or rubber.
[0025] In any of the above structures, the length of the elastic
body is preferably a natural length or longer in a state where the
light-emitting device is opened. Note that the natural length here
means the length of the elastic body (such as a spring or rubber)
to which no load is applied (i.e., the length of the elastic body
not expanding or contracting).
[0026] In any of the above structures, a protective layer is
preferably further included. The first region includes a portion
where the connection portion and the light-emitting panel overlap
with each other with the protective layer positioned therebetween.
The second region includes a portion where the first support and
the light-emitting panel overlap with each other with the
protective layer positioned therebetween. The third region includes
a portion where the second support and the light-emitting panel
overlap with each other with the protective layer positioned
therebetween.
[0027] In any of the above structures, in the first region, the
plurality of spacers each preferably include a portion fixed to the
protective layer.
[0028] In any of the above structures, in the first region, the
protective layer preferably includes a portion fixed to the
light-emitting panel.
[0029] In any of the above structures, the width of a first surface
of the spacer on the light-emitting panel side is larger than the
width of a second surface of the spacer on the side opposite to the
light-emitting panel side.
[0030] In the above, the light-emitting device including the
light-emitting panel is described as an example; however, a display
device or an input/output device to which any of the above
structures is applied is also one embodiment of the present
invention. A display device of one embodiment of the present
invention includes a display panel. An input/output device of one
embodiment of the present invention includes a touch panel.
[0031] One embodiment of the present invention is a module
including a light-emitting device, a display device, or an
input/output device to which any of the above structures is
applied. The module is provided with a connector such as a flexible
printed circuit (FPC) or a tape carrier package (TCP) or is mounted
with an IC by a chip on glass (COG) method or the like.
[0032] An electronic device or a lighting device including the
above module is also one embodiment of the present invention. For
example, one embodiment of the present invention is an electronic
device including the above module and at least one of an antenna, a
battery, a housing, a speaker, a microphone, an operation switch,
and an operation button.
[0033] According to one embodiment of the present invention, a
highly portable light-emitting device, display device, input/output
device, electronic device, or lighting device can be provided.
According to one embodiment of the present invention, a highly
browsable light-emitting device, display device, input/output
device, or electronic device can be provided. According to one
embodiment of the present invention, a highly portable and highly
browsable light-emitting device, display device, input/output
device, or electronic device can be provided.
[0034] According to one embodiment of the present invention, a
novel light-emitting device, display device, input/output device,
electronic device, or lighting device can be provided. According to
one embodiment of the present invention, a light-emitting device,
display device, input/output device, electronic device, or lighting
device that is less likely to be broken can be provided. According
to one embodiment of the present invention, a highly reliable
light-emitting device, display device, input/output device,
electronic device, or lighting device can be provided. According to
one embodiment of the present invention, a light-emitting device,
display device, input/output device, electronic device, or lighting
device with low power consumption can be provided.
[0035] According to one embodiment of the present invention, a
lightweight light-emitting device or the like can be provided.
According to one embodiment of the present invention, a thin
light-emitting device or the like can be provided. According to one
embodiment of the present invention, a flexible light-emitting
device or the like can be provided. According to one embodiment of
the present invention, a light-emitting device or lighting device
with a seamless large light-emitting region or a display device,
input/output device, or electronic device with a seamless large
display region can be provided.
[0036] Note that the description of these effects does not disturb
the existence of other effects. One embodiment of the present
invention does not necessarily achieve all the effects listed
above. Other effects can be derived from the description of the
specification, the drawings, and the claims.
BRIEF DESCRIPTION OF DRAWINGS
[0037] FIGS. 1A to 1C illustrate an example of a light-emitting
device.
[0038] FIGS. 2A to 2C illustrate an example of a light-emitting
device.
[0039] FIGS. 3A to 3C illustrate an example of a light-emitting
device.
[0040] FIGS. 4A and 4B illustrate examples of a connection portion
and a spacer.
[0041] FIG. 5 illustrates an example of a connection portion.
[0042] FIGS. 6A and 6B each illustrate an example of a
light-emitting device.
[0043] FIGS. 7A to 7C illustrate examples of a light-emitting
device.
[0044] FIGS. 8A to 8C illustrate an example of a light-emitting
device.
[0045] FIGS. 9A to 9C illustrate an example of a light-emitting
device.
[0046] FIGS. 10A to 10C illustrate an example of a light-emitting
device.
[0047] FIGS. 11A to 11C illustrate an example of a light-emitting
device.
[0048] FIGS. 12A to 12C illustrate examples of a light-emitting
device.
[0049] FIGS. 13A to 13C illustrate examples of a light-emitting
device.
[0050] FIGS. 14A and 14B illustrate an example of a light-emitting
panel.
[0051] FIGS. 15A and 15B illustrate an example of a light-emitting
panel.
[0052] FIGS. 16A to 16D illustrate examples of a light-emitting
panel.
[0053] FIGS. 17A and 17B illustrate examples of a light-emitting
panel.
[0054] FIGS. 18A to 18C illustrate an example of a touch panel.
[0055] FIGS. 19A and 19B illustrate an example of a touch
panel.
[0056] FIGS. 20A and 20B each illustrate an example of a touch
panel.
[0057] FIGS. 21A to 21C illustrate examples of a touch panel.
[0058] FIGS. 22A to 22C are photographs of a light-emitting device
in Example.
[0059] FIGS. 23A to 23C are photographs of a light-emitting device
in Example.
BEST MODE FOR CARRYING OUT THE INVENTION
[0060] Embodiments will be described in detail with reference to
the accompanying drawings. Note that the present invention is not
limited to the description below, and it is easily understood by
those skilled in the art that various changes and modifications can
be made without departing from the spirit and scope of the present
invention. Therefore, the present invention should not be construed
as being limited to the description in the following
embodiments.
[0061] Note that in the structures of the invention described
below, the same portions or portions having similar functions are
denoted by the same reference numerals in different drawings, and
description of such portions is not repeated. Further, the same
hatching pattern is applied to portions having similar functions,
and the portions are not especially denoted by reference numerals
in some cases.
[0062] The position, size, range, or the like of each structure
illustrated in drawings is not accurately represented in some cases
for easy understanding. Therefore, the disclosed invention is not
necessarily limited to the position, size, range, or the like
disclosed in the drawings.
[0063] Note that the terms "film" and "layer" can be interchanged
with each other depending on the case or circumstances. For
example, the term "conductive film" can be used instead of the term
"conductive layer," and the term "insulating layer" can be used
instead of the term "insulating film."
Embodiment 1
[0064] In this embodiment, a light-emitting device of one
embodiment of the present invention will be described with
reference to FIGS. 1A to 1C, FIGS. 2A to 2C, FIGS. 3A to 3C, FIGS.
4A and 4B, FIG. 5, FIGS. 6A and 6B, FIGS. 7A to 7C, FIGS. 8A to 8C,
FIGS. 9A to 9C, FIGS. 10A to 10C, FIGS. 11A to 11C, FIGS. 12A to
12C, and FIGS. 13A to 13C.
[0065] Although a light-emitting device mainly including an organic
EL element is described in this embodiment as an example, one
embodiment of the present invention is not limited to this example.
A light-emitting device or a display device including another
light-emitting element or display element which will be described
in Embodiment 2 as an example is also one embodiment of the present
invention. Moreover, one embodiment of the present invention is not
limited to the light-emitting device or the display device and can
be applied to a variety of devices such as an input/output
device.
[0066] A light-emitting device of one embodiment of the present
invention includes a strip-like region with high flexibility and a
strip-like region with low flexibility that are arranged
alternately. The light-emitting device can be folded by bending the
region with high flexibility. The light-emitting device of one
embodiment of the present invention is highly portable in a folded
state, and is highly browsable in an opened state because of a
seamless large light-emitting region.
[0067] In the light-emitting device of one embodiment of the
present invention, the region with high flexibility can be bent
inwardly or outwardly. In the light-emitting device of this
embodiment, one light-emitting panel can be folded once or more
times. The radius of curvature in that case can be, for example,
greater than or equal to 0.01 mm and less than or equal to 150
mm.
[0068] Note that in this specification, being "bent inwardly" means
being bent such that a light-emitting surface of a light-emitting
panel faces inward, and being "bent outwardly" means being bent
such that a light-emitting surface of a light-emitting panel faces
outward. A light-emitting surface of a light-emitting panel or a
light-emitting device refers to a surface through which light
emitted from a light-emitting element is extracted.
[0069] When the light-emitting device of one embodiment of the
present invention is not in use, it can be folded such that a
light-emitting surface of a light-emitting panel faces inward,
whereby the light-emitting surface can be prevented from being
damaged or contaminated.
[0070] When the light-emitting device of one embodiment of the
present invention is in use, it can be opened so that the seamless
large light-emitting region is entirely used, or it can be folded
such that the light-emitting surface of the light-emitting panel
faces outward and the light-emitting region can be partly used.
Folding the light-emitting device and putting part of the
light-emitting region that is hidden from a user in a
non-light-emitting state can reduce the power consumption of the
light-emitting device.
[0071] One embodiment of the present invention is a light-emitting
device having a first region, a second region, and a third region.
The first region is positioned between the second region and the
third region. The first region has the highest flexibility of the
first to third regions. The second region includes a light-emitting
panel and a first support which overlap with each other. The third
region includes the light-emitting panel and a second support which
overlap with each other. Note that the light-emitting panel has
higher flexibility than the first support and the second
support.
[0072] The first region includes the light-emitting panel and a
plurality of spacers. In the first region, the plurality of spacers
each overlap with the light-emitting panel.
[0073] In the first region that has high flexibility, the
light-emitting panel and a member (here, the spacers) are
positioned so as to overlap with each other; thus, the first region
can have high mechanical strength and high resistance to bending as
compared with the case where the first region includes only the
light-emitting panel.
[0074] However, when the light-emitting panel and the member are
positioned so as to overlap with each other, a neutral plane (a
plane which does not expand or contract) in which distortion of
stress, such as compressive stress or tensile stress, due to
deformation such as bending might be positioned apart from the
light-emitting panel. As the neural plane is farther from the
light-emitting panel, comparative stress or tensile stress due to
bending is more applied to the light-emitting panel; thus, the
light-emitting panel is likely to be broken.
[0075] In view of the above, the light-emitting device of one
embodiment of the present invention has a structure in which, when
the first region is bent, the angle between normals of facing
planes of the two adjacent spacers changes according to the bending
of the light-emitting panel. With such a structure, the neutral
plane can be prevented from being apart from the light-emitting
panel. The neutral plane is formed close to the light-emitting
panel or in the light-emitting panel, whereby the light-emitting
panel cannot easily expand or contract even when the light-emitting
device is bent. Accordingly, the light-emitting panel can be
prevented from being broken owing to the folding.
[0076] An example of a light-emitting device that has two regions
having low flexibility and one region having high flexibility
between the two regions and can be folded in two parts will be
described below. In this embodiment, a region having high
flexibility and a region having low flexibility or regions with low
flexibility are parallel to each other; however, the regions are
not necessarily arranged parallel to each other.
STRUCTURE EXAMPLE A
[0077] FIG. 1A illustrates a light-emitting device that is opened.
FIG. 1B illustrates the light-emitting device that is being opened
or being folded. FIG. 1C illustrates the light-emitting device that
is folded.
[0078] The light-emitting device has a first region 151, a second
region 152, and a third region 153. The first region 151 is
positioned between the second region 152 and the third region 153.
The first region 151 has the highest flexibility of the three
regions.
[0079] The light-emitting device includes a light-emitting panel
101, a support 103(1), a support 103(2), and a plurality of spacers
108.
[0080] The light-emitting panel 101 has a light-emitting region 111
(also referred to as a light-emitting portion, a pixel portion, or
a display portion) and a non-light-emitting region 112. The
non-light-emitting region 112 is provided so as to surround the
light-emitting region 111.
[0081] The light-emitting panel 101 is flexible. A light-emitting
panel using organic EL elements is particularly preferable, in
which case it can have high flexibility and impact resistance, and
in addition, can be thinner and more lightweight.
[0082] The support 103(1) and the support 103(2) are apart from
each other. The two supports each have lower flexibility than the
light-emitting panel 101.
[0083] The first region 151 includes the light-emitting panel 101
and the plurality of spacers 108. The plurality of spacers 108 each
overlap with the light-emitting panel 101. The plurality of spacers
108 are each fixed to the light-emitting panel 101. The adjacent
spacers 108 are not fixed to each other. With such a structure,
when the first region 151 is bent, the angle between normals of
facing planes of the two adjacent spacers 108 changes according to
the bending of the light-emitting panel 101. Accordingly, a neutral
plane can be formed in the light-emitting panel 101 or in the
vicinity of the light-emitting panel 101.
[0084] Some of the spacers 108 may be positioned in a region which
does not overlap with the light-emitting panel 101. Alternatively,
all the spacers 108 may overlap with the light-emitting panel
101.
[0085] In this embodiment, the spacers 108 are positioned on the
side opposite to the light-emitting surface side of the
light-emitting panel 101; however, one embodiment of the present
invention is not limited thereto. For example, the spacers 108 may
be positioned on the light-emitting surface side of the
light-emitting panel 101. In the case where the spacers 108 are
positioned on the light-emitting surface side of the light-emitting
panel 101, the spacers 108 preferably overlap with only the
non-light-emitting region 112. In the case where the spacers 108
overlap with the light-emitting region 111, a material which
transmits visible light is preferably used for the spacers 108.
[0086] In the second region 152, the light-emitting panel 101 and
the support 103(1) overlap with each other. The support 103(1) is
positioned on the side opposite to the light-emitting surface side
of the light-emitting panel 101. The light-emitting panel 101 and
the support 103(1) may be fixed to each other.
[0087] In the third region 153, the light-emitting panel 101 and
the support 103(2) overlap with each other. The support 103(2) is
positioned on the side opposite to the light-emitting surface side
of the light-emitting panel 101. The light-emitting panel 101 and
the support 103(2) may be fixed to each other.
[0088] The supports are preferably provided only on the side
opposite to the light-emitting surface side of the light-emitting
panel 101 because the light-emitting device can be thin and
lightweight.
STRUCTURE EXAMPLE B
[0089] FIG. 2A illustrates a light-emitting device that is opened.
FIG. 2B illustrates the light-emitting device that is being opened
or being folded. FIG. 2C illustrates the light-emitting device that
is folded. Note that in the following structure examples (including
modification examples), description of structures similar to those
described in any of the above structure examples is omitted in some
cases.
[0090] The light-emitting device includes the light-emitting panel
101, a support 103a(1), a support 103a(2), a support 103b(1), a
support 103b(2), and a connection portion 105.
[0091] The support 103a(1) and the support 103a(2) are apart from
each other. The support 103b(1) and the support 103b(2) are apart
from each other. The four supports each have lower flexibility than
the light-emitting panel 101.
[0092] In the second region 152, the light-emitting panel 101 is
provided between the support 103a(1) and the support 103b(1). The
support 103a(1) is positioned on the light-emitting surface side of
the light-emitting panel 101. The support 103b(1) is positioned on
the side opposite to the light-emitting surface side of the
light-emitting panel 101. The light-emitting panel 101 may be fixed
to at least one of the support 103a(1) and the support 103b(1).
[0093] In the third region 153, the light-emitting panel 101 is
provided between the support 103a(2) and the support 103b(2). The
support 103a(2) is positioned on the light-emitting surface side of
the light-emitting panel 101. The support 103b(2) is positioned on
the side opposite to the light-emitting surface side of the
light-emitting panel 101. The light-emitting panel 101 may be fixed
to at least one of the support 103a(2) and the support 103b(2).
[0094] The supports are preferably provided on both the
light-emitting surface side and the side opposite to the
light-emitting surface side of the light-emitting panel 101 because
the light-emitting panel 101 can be sandwiched between the pair of
supports and thus the mechanical strength of a region having low
flexibility can be increased. As a result, the light-emitting
device can be less likely to be broken.
[0095] The first region 151 includes the light-emitting panel 101
and the connection portion 105. The light-emitting panel 101 and
the connection portion 105 overlap with each other.
[0096] FIGS. 3A to 3C are side views of the connection portion 105
in the states shown in FIGS. 2A to 2C, respectively. FIG. 4A and
FIG. 5 are each an example of a top view of the connection portion
105. FIG. 4B is a perspective view of the spacer 108.
[0097] The connection portion 105 includes an elastic body 106 and
the plurality of spacers 108.
[0098] In FIGS. 3A to 3C, FIG. 4A, and FIG. 5, the elastic body 106
is shown with a thin solid line; however, in an actual structure,
the elastic body 106 is not exposed on the outside of the spacers
108 but positioned in openings provided in the spacers 108.
[0099] One end portion of the elastic body 106 is fixed to the
support 103b(1), and the other end portion of the elastic body 106
is fixed to the support 103b(2). That is, the elastic body 106
connects the support 103b(1) and the support 103b(2).
[0100] The openings are provided in the spacers 108. The spacers
108 are connected to each other through the elastic body 106.
Specifically, the elastic body 106 connects the plurality of
spacers 108 through the openings. There is no particular limitation
on the number of the openings in the spacers 108.
[0101] There is no particular limitation on the number of the
spacers 108.
[0102] The number of the spacers 108 in the light-emitting device
may be one. In the case where one spacer 108 is provided in the
light-emitting device, the angle between normals of facing planes
of the spacer 108 and the support needs to change according to the
bending of the light-emitting panel. With such a structure, the
neutral plane can be prevented from being apart from the
light-emitting panel.
[0103] The number of the spacers 108 in the light-emitting device
is preferably two or more.
[0104] In the example of FIG. 4A, 10 spacers 108 are arranged in
one direction. In the example of FIG. 5, there are two lines in
each of which 10 spacers 108 are arranged in one direction, and the
connection portion 105 includes 20 spacers 108 in total.
[0105] The number of the spacers 108 arranged in one line is
preferably larger because the light-emitting device can be bent
more smoothly. Furthermore, the width (the length in the short-side
direction) of each of the spacers 108 is preferably narrower
because the light-emitting device can be bent more smoothly. The
light-emitting device can have high resistance to bending when a
large number of spacers 108 each having a small width are
arranged.
[0106] In the structure of FIG. 5, the spacers 108 are arranged in
two lines, and there is a space between the two lines. On the other
hand, in the structure of FIG. 4A, the spacers 108 are arranged in
one line, and thus there is no space. Therefore, a bent portion of
the light-emitting panel is less likely to be exposed when the
light-emitting device is folded; thus, the light-emitting panel can
be prevented from being damaged and elements in the light-emitting
panel can be prevented from being broken.
[0107] The plurality of spacers 108 each overlap with the
light-emitting panel 101. The plurality of spacers 108 are
connected to each other through the elastic body 106 in the
openings, but are not fixed to each other. With such a structure,
when the first region 151 is bent, the angle between normals of
facing planes of the two adjacent spacers 108 changes according to
the bending of the light-emitting panel 101. Accordingly, a neutral
plane can be formed in the light-emitting panel 101 or in the
vicinity of the light-emitting panel 101.
[0108] An enlarged view of two adjacent spacers 108 is shown in the
upper right portion of FIG. 3C. In FIG. 3C, an angle .theta.
between the normals of the facing planes of the two adjacent
spacers 108 is an acute angle. As the light-emitting device is
opened from the state of FIG. 3C, the angle .theta. becomes
smaller. When the angle .theta. becomes 0.degree. in the state of
FIG. 3A, that is, when the facing planes of the two adjacent
spacers 108 are in contact with each other, the light-emitting
device cannot be further bent. That is, the first region 151 in
this case can be regarded as a portion that cannot be outwardly
bent.
[0109] In this example, the spacers 108 are positioned on the side
opposite to the light-emitting surface side of the light-emitting
panel 101 and the first region 151 can be inwardly bent but cannot
be outwardly bent; however, one embodiment of the present invention
is not limited thereto. In the case where the spacers 108 are
positioned on the light-emitting surface side of the light-emitting
panel 101, the first region 151 can be outwardly bent but cannot be
inwardly bent.
[0110] It is possible to bend the light-emitting device illustrated
in FIG. 3C with a radius of curvature smaller than that shown in
FIG. 3C. However, there is a possibility that the light-emitting
panel 101 is broken when the light-emitting panel 101 is bent with
too small a radius of curvature. In order to prevent that, the
support 103b(1) and the support 103b(2) are preferably kept at a
certain distance from each other by adjusting the thicknesses of
the support 103a(1) and the support 103a(2) or providing a fixing
unit for fixing the two supports to each other, for example. In
this case, the light-emitting panel 101 can be prevented from being
bent with too small a radius of curvature.
[0111] The range in which the light-emitting device can be bent at
the first region 151 can be controlled by adjusting the shapes or
the number of the spacers 108.
[0112] For example, there is no particular limitation on the
cross-sectional shape of the spacer 108 along the direction
perpendicular to the longitudinal direction, and it may be a circle
or a polygon (including a polygon with rounded corners) such as a
triangle, a quadrangle, a pentagon, or a hexagon.
[0113] For example, as described in this Structure Example B, as
the cross-sectional shape of the spacer 108 along the direction
perpendicular to the longitudinal direction, a shape in which two
facing side surfaces of the spacer 108 (two surfaces facing the
respective adjacent spacers 108) are parallel to each other, such
as a square, a rectangle, or a parallelogram, can be used. In this
case, a region having high flexibility can be either inwardly or
outwardly bent.
[0114] Alternatively, for example, as described below in Structure
Example D, the cross-sectional shape of the spacer 108 along the
direction perpendicular to the longitudinal direction can be a
shape in which two facing side surfaces of the spacer 108 are not
parallel to each other, such as a trapezoid. In this case, a region
having high flexibility can be inwardly and outwardly bent.
[0115] The plurality of spacers 108 are each preferably fixed to
the light-emitting panel 101 because the spacers 108 can be
prevented from being moved in the longitudinal direction of the
spacers 108.
[0116] For the elastic body 106, a spring or rubber can be used,
for example. In the light-emitting device that is opened, the
length of the elastic body 106 is preferably a natural length or
longer. In this case, the light-emitting device can be easily kept
opened. On the other hand, in order to easily keep the
light-emitting device folded, the length of the elastic body 106 is
made shorter than the natural length when the light-emitting device
is opened.
MODIFICATION EXAMPLE 1
[0117] FIGS. 6A and 6B are each a top view of a light-emitting
device that is opened.
[0118] In the case of the light-emitting device illustrated in FIG.
6A, both the light-emitting region 111 and the non-light-emitting
region 112 are seen by a user viewing a light-emitting surface of
the light-emitting device.
[0119] In the case of the light-emitting device illustrated in FIG.
6B, the non-light-emitting region 112 is not seen and only the
light-emitting region 111 is seen by a user viewing a
light-emitting surface of the light-emitting device.
[0120] The light-emitting device illustrated in FIG. 6A is a
modification example of Structure Example B, but may be applied to
Structure Example A. Similarly, the light-emitting device
illustrated in FIG. 6B is a modification example of Structure
Example A, but may be applied to Structure Example B.
[0121] In the light-emitting devices illustrated in FIGS. 6A and
6B, a light-blocking layer 109 is provided. The light-blocking
layer 109 overlaps with the connection portion 105 or the spacers
108. Since the light-blocking layer 109 is positioned so as to
overlap with the connection portion 105 or the spacers 108, the
connection portion 105 or the spacers 108 can be prevented from
being seen by a user viewing the light-emitting surface of the
light-emitting device.
[0122] The light-blocking layer 109 may overlap with the
non-light-emitting region 112 of the light-emitting panel. When the
light-blocking layer 109 is positioned so as to overlap with the
non-light-emitting region 112, the non-light-emitting region 112
can be prevented from being irradiated with external light.
Accordingly, photodegradation of a transistor and the like of a
driver circuit that is included in the non-light-emitting region
112 can be prevented.
[0123] For the light-blocking layer 109, a flexible material that
can block light is used. For example, resin, plastic, metal, alloy,
rubber, paper, or the like can be used. A film or a tape formed
using any of them may be used. Note that a bonding layer may be
provided between the light-blocking layer 109 and the connection
portion 105.
MODIFICATION EXAMPLE 2
[0124] FIG. 7A is a top view of a light-emitting device that is
opened. FIG. 7B is a side view of the light-emitting device that is
folded.
[0125] The light-emitting device illustrated in FIGS. 7A and 7B
includes one spacer 108. In the spacer 108, a plurality of cuts are
provided. A plurality of projections separated by the cuts function
like the plurality of spacers described in the above structure
examples. That is, when the first region 151 is bent, the angle
between normals of facing planes of the two adjacent projections
changes according to the bending of the light-emitting panel 101.
Accordingly, a neutral plane can be formed in the light-emitting
panel 101 or in the vicinity of the light-emitting panel 101. The
cuts are preferably formed deeply because a neutral plane can be
easily formed in the light-emitting panel 101 or in the vicinity of
the light-emitting panel 101. Note that two or more spacers 108
each having a cut may be provided.
[0126] The light-emitting device illustrated in FIGS. 7A and 7B
includes a fixing unit 107. With the fixing unit 107, the
light-emitting panel 101 can be prevented from being bent with too
small a radius of curvature when the light-emitting device is
folded, and thus the light-emitting device can be prevented from
being broken. As the fixing unit 107, a magnet-type or
mechanical-type fixing unit can be used. The fixing unit 107 can
keep the light-emitting device folded.
MODIFICATION EXAMPLE 3
[0127] FIG. 7C is a side view of a light-emitting device that is
opened. The light-emitting device illustrated in FIG. 7C is a
modification example of the light-emitting device illustrated in
FIGS. 3A to 3C.
[0128] A protective layer 113a may be provided on a light-emitting
surface of the light-emitting panel 101. In the case where the
protective layer 113a transmits visible light, the protective layer
113a can be positioned so as to overlap with the light-emitting
region 111. In the case where the protective layer 113a does not
transmit visible light, the protective layer 113a has an opening in
a portion overlapping with the light-emitting region 111. The
protective layer 113a may also serve as the light-blocking layer
109.
[0129] A protective layer 113b may be provided between the
light-emitting panel 101 and the connection portion 105. The
protective layer 113b is fixed to the connection portion 105. For
example, the plurality of spacers 108 are each fixed to the
protective layer 113b, in which case the spacers 108 can be
prevented from being moved in the longitudinal direction of the
spacers 108.
[0130] The protective layer 113b is also preferably fixed to the
light-emitting panel 101. In particular, in a region where the
light-emitting panel 101, the protective layer 113b, and the
connection portion 105 overlap with one another, the protective
layer 113b is preferably fixed to the light-emitting panel 101. In
that case, the mechanical strength of the first region 151 with
high flexibility can be further increased.
[0131] The protective layer 113b is preferably thinner because a
neutral plane is less likely to be apart from the light-emitting
panel 101 and the light-emitting panel 101 can be prevented from
being broken. The protective layer 113b is positioned on the side
opposite to the light-emitting surface side of the light-emitting
panel 101, and thus the protective layer 113b does not necessarily
transmit visible light. The protective layer 113b is preferably
thicker because the mechanical strength of the light-emitting
device can be increased and thus the light-emitting panel 101 can
be effectively protected. The thickness of the protective layer
113b can be, for example, 0.01 to 10 times, preferably 0.05 to 5
times, more preferably 0.05 to 3 times as large as the thickness of
the light-emitting panel 101.
[0132] The protective layer 113b can be positioned so as to overlap
with both the light-emitting region 111 and the non-light-emitting
region 112. A region where the protective layer 113b and the
light-emitting panel 101 overlap with each other preferably has a
larger area because the light-emitting panel 101 can be more
effectively protected and the reliability of the light-emitting
device can be improved. For example, the protective layer 113b is
positioned so as to overlap with at least one of (preferably, each
of) the support 103a(1), the support 103a(2), the support 103b(1),
and the support 103b(2).
[0133] The protective layers preferably have higher flexibility
than the supports. Furthermore, the protective layers are
preferably thinner than the supports.
[0134] When at least one of the protective layer 113a and the
protective layer 113b is provided, a region with high flexibility
can also have high mechanical strength; thus, the light-emitting
device can be less likely to be broken. This structure makes the
light-emitting device less likely to be broken by deformation due
to external force or the like in the region with high flexibility
as well as a region with low flexibility.
[0135] In the case where one of the protective layer 113a and the
protective layer 113b is provided, the light-emitting device can be
thinner and more lightweight.
[0136] In the case where both the protective layer 113a and the
protective layer 113b are provided, the light-emitting panel can be
sandwiched between the pair of protective layers and thus the
mechanical strength of the light-emitting device can be increased;
as a result, the light-emitting device can be less likely to be
broken.
EXAMPLES OF MATERIALS FOR LIGHT-EMITTING DEVICE
[0137] There is no particular limitation on materials for the
spacer, the protective layer, and the support; they can each be
formed using plastic, metal, alloy, rubber, or the like, for
example. Plastic, rubber, or the like is preferably used because it
can form a spacer, a protective layer, or a housing that is
lightweight and less likely to be broken. For example, silicone
rubber may be used for the protective layer and stainless steel or
aluminum may be used for the spacer and the support.
[0138] The spacer, the protective layer, and the support are each
preferably formed using a material with high toughness. In that
case, a light-emitting device with high impact resistance that is
less likely to be broken can be provided. For example, when an
organic resin, a thin metal material, or a thin alloy material is
used for the spacer, the protective layer, and the support, the
light-emitting device can be lightweight and less likely to be
broken. For a similar reason, also a substrate of the
light-emitting panel is preferably formed using a material with
high toughness.
[0139] The spacer, the protective layer, and the support on the
light-emitting surface side do not necessarily have a
light-transmitting property if they do not overlap with the
light-emitting region of the light-emitting panel. When the spacer,
the protective layer, and the support on the light-emitting surface
side overlap with at least part of the light-emitting region, they
are preferably formed using a material that transmits light emitted
from the light-emitting panel. There is no limitation on the
light-transmitting property of the spacer, the protective layer,
and the support on the side opposite to the light-emitting surface
side.
[0140] When any two of the spacer, the protective layer, the
support, and the light-emitting panel are bonded to each other, any
of a variety of adhesives can be used, and for example, a curable
resin that is curable at room temperature (e.g., a
two-component-mixture-type resin), a light curable resin, a heat
curable resin, or the like can be used. Alternatively, a sheet-like
adhesive may be used. Alternatively, components of the
light-emitting device may be fixed with, for example, a screw that
penetrates two or more of the spacer, the protective layer, the
support, and the light-emitting panel or a pin or clip that holds
them.
[0141] The light-emitting device of one embodiment of the present
invention can be used with one light-emitting panel (one
light-emitting region) divided into two or more regions at a folded
portion(s). For example, it is possible to put the region that is
hidden by folding the light-emitting device in a non-light-emitting
state and put only the exposed region in a light-emitting state.
Thus, power consumed by a region that is not used by a user can be
reduced.
[0142] The light-emitting device of one embodiment of the present
invention may include a sensor for determining whether each region
with high flexibility is bent or not. The sensor can be composed
of, for example, a switch such as a magnetic switch or a pressure
sensor such as a MEMS pressure sensor.
[0143] A light-emitting device that includes two regions with high
flexibility and three regions with low flexibility and can be
folded in three parts is described below as an example. In this
embodiment, an example in which one of the two regions with high
flexibility is bent inwardly and the other is bent outwardly is
described; however, one embodiment of the present invention is not
limited thereto. That is, when a light-emitting device having a
plurality of regions with high flexibility is folded, a
light-emitting panel is not necessarily bent inwardly and outwardly
alternately. All the plurality of regions with high flexibility may
be bent either inwardly or outwardly. Furthermore, the plurality of
regions with high flexibility may be bent inwardly plural times and
outwardly plural times.
STRUCTURE EXAMPLE C
[0144] FIG. 8A illustrates a light-emitting device that is opened.
FIG. 8B illustrates the light-emitting device that is being opened
or being folded. FIG. 8C illustrates the light-emitting device that
is folded.
[0145] The light-emitting device has a first region 161, a second
region 162, a third region 163, a fourth region 164, and a fifth
region 165. The first region 161 is positioned between the second
region 162 and the third region 163. The first region 161 has the
highest flexibility of the first to third regions. The fourth
region 164 is positioned between the third region 163 and the fifth
region 165. The fourth region 164 has the highest flexibility of
the third to fifth regions.
[0146] The light-emitting device includes the light-emitting panel
101, the support 103(1), the support 103(2), a support 103(3), a
connection portion 105a, and a connection portion 105b.
[0147] The light-emitting panel 101 has the light-emitting region
111 and the non-light-emitting region 112. The non-light-emitting
region 112 is provided so as to surround the light-emitting region
111.
[0148] The support 103(1) and the support 103(2) are apart from
each other. The support 103(2) and the support 103(3) are apart
from each other. The three supports each have lower flexibility
than the light-emitting panel 101.
[0149] The first region 161 includes the light-emitting panel 101
and the connection portion 105a. The light-emitting panel 101 and
the connection portion 105a overlap with each other.
[0150] The fourth region 164 includes the light-emitting panel 101
and the connection portion 105b. The light-emitting panel 101 and
the connection portion 105b overlap with each other.
[0151] The first region 161 is a portion at which the
light-emitting panel 101 can be bent outwardly. The details of the
connection portion 105a will be described later in Structure
Example D.
[0152] The fourth region 164 is a portion at which the
light-emitting panel 101 can be bent inwardly. For the details of
the connection portion 105b, the description of the connection
portion 105 in Structure Example B can be referred to.
[0153] In the second region 162, the light-emitting panel 101 and
the support 103(1) overlap with each other. The support 103(1) is
positioned on the side opposite to the light-emitting surface side
of the light-emitting panel 101. The light-emitting panel 101 and
the support 103(1) may be fixed to each other.
[0154] In the third region 163, the light-emitting panel 101 and
the support 103(2) overlap with each other. The support 103(2) is
positioned on the side opposite to the light-emitting surface side
of the light-emitting panel 101. The light-emitting panel 101 and
the support 103(2) may be fixed to each other.
[0155] In the fifth region 165, the light-emitting panel 101 and
the support 103(3) overlap with each other. The support 103(3) is
positioned on the side opposite to the light-emitting surface side
of the light-emitting panel 101. The light-emitting panel 101 and
the support 103(3) may be fixed to each other.
[0156] The supports are preferably provided only on the side
opposite to the light-emitting surface side of the light-emitting
panel 101 because the light-emitting device can be thin and
lightweight.
STRUCTURE EXAMPLE D
[0157] FIG. 9A illustrates a light-emitting device that is opened.
FIG. 9B illustrates the light-emitting device that is being opened
or being folded. FIG. 9C illustrates the light-emitting device that
is folded.
[0158] The light-emitting device includes the light-emitting panel
101, the support 103a(1), the support 103a(2), a support 103a(3),
the support 103b(1), the support 103b(2), a support 103b(3), the
connection portion 105a, and the connection portion 105b.
[0159] The support 103a(1) and the support 103a(2) are apart from
each other. The support 103a(2) and the support 103a(3) are apart
from each other. The support 103b(1) and the support 103b(2) are
apart from each other. The support 103b(2) and the support 103b(3)
are apart from each other. The six supports each have lower
flexibility than the light-emitting panel 101.
[0160] The first region 161 includes the light-emitting panel 101
and the connection portion 105a. The light-emitting panel 101 and
the connection portion 105a overlap with each other.
[0161] The fourth region 164 includes the light-emitting panel 101
and the connection portion 105b. The light-emitting panel 101 and
the connection portion 105b overlap with each other.
[0162] In the second region 162, the light-emitting panel 101 is
provided between the support 103a(1) and the support 103b(1). The
support 103a(1) is positioned on the light-emitting surface side of
the light-emitting panel 101. The support 103b(1) is positioned on
the side opposite to the light-emitting surface side of the
light-emitting panel 101. The light-emitting panel 101 may be fixed
to at least one of the support 103a(1) and the support 103b(1).
[0163] In the third region 163, the light-emitting panel 101 is
provided between the support 103a(2) and the support 103b(2). The
support 103a(2) is positioned on the light-emitting surface side of
the light-emitting panel 101. The support 103b(2) is positioned on
the side opposite to the light-emitting surface side of the
light-emitting panel 101. The light-emitting panel 101 may be fixed
to at least one of the support 103a(2) and the support 103b(2).
[0164] In the fifth region 165, the light-emitting panel 101 is
provided between the support 103a(3) and the support 103b(3). The
support 103a(3) is positioned on the light-emitting surface side of
the light-emitting panel 101. The support 103b(3) is positioned on
the side opposite to the light-emitting surface side of the
light-emitting panel 101. The light-emitting panel 101 may be fixed
to at least one of the support 103a(3) and the support 103b(3).
[0165] The supports are preferably provided on both the
light-emitting surface side and the side opposite to the
light-emitting surface side of the light-emitting panel 101 because
the light-emitting panel 101 can be sandwiched between the pair of
supports and thus the mechanical strength of a region having low
flexibility can be increased. As a result, the light-emitting
device can be less likely to be broken.
[0166] FIGS. 10A to 10C are side views of the connection portion
105a in the states shown in FIGS. 9A to 9C, respectively.
[0167] The connection portion 105a includes the elastic body 106
and the plurality of spacers 108. In Structure Example D, a
cross-sectional shape of the spacer 108 along the direction
perpendicular to the longitudinal direction of the spacer 108 is a
trapezoid. In this case, in the first region 161, a region with
high flexibility can be bent inwardly and outwardly.
[0168] In FIGS. 10A to 10C, the elastic body 106 is shown with a
thin solid line; however, in an actual structure, the elastic body
106 is not exposed on the outside of the spacers 108 but positioned
in openings provided in the spacers 108.
[0169] One end portion of the elastic body 106 is fixed to the
support 103b(1), and the other end portion of the elastic body 106
is fixed to the support 103b(2). That is, the elastic body 106
connects the support 103b(1) and the support 103b(2).
[0170] The openings are provided in the spacers 108. The elastic
body 106 connects the plurality of spacers 108 through the
openings.
[0171] The plurality of spacers 108 each overlap with the
light-emitting panel 101. The plurality of spacers 108 are
connected to each other through the elastic body 106 in the
openings, but are not fixed to each other. With such a structure,
when the first region 161 is bent, the angle between normals of
facing planes of the two adjacent spacers 108 changes according to
the bending of the light-emitting panel 101. Accordingly, a neutral
plane can be formed in the light-emitting panel 101 or in the
vicinity of the light-emitting panel 101.
[0172] An enlarged view of two adjacent spacers 108 is shown in the
lower left portion of FIG. 10A. In FIG. 10A, an angle .theta.
between the normals of the facing planes of the two adjacent
spacers 108 is an acute angle. As the light-emitting device is bent
from the state of FIG. 10A, the angle .theta. becomes smaller. When
the angle .theta. becomes 0.degree. in the state of FIG. 10C, the
light-emitting device cannot be further bent. That is, depending on
the shape or the number of the spacers 108, the light-emitting
panel 101 can be prevented from being bent with too small a radius
of curvature when the light-emitting device is folded at the first
region 161.
[0173] The light-emitting device can also be bent inwardly at the
first region 161 because the angle .theta. can be larger than in
the state of FIG. 10A.
[0174] The width or the area of the surface of the spacer 108 on
the light-emitting panel 101 side is preferably larger than that on
the opposite side because the light-emitting panel 101 can be bent
outwardly in the light-emitting device. The shape of the side
surface of the spacer 108 is, for example, a trapezoid as
illustrated in FIG. 10A. Note that corner portions of the spacer
108 may have curvature.
[0175] The plurality of spacers 108 are each preferably fixed to
the light-emitting panel 101 because the spacers 108 can be
prevented from being moved in the longitudinal direction of the
spacers 108.
STRUCTURE EXAMPLE E
[0176] FIG. 11A illustrates a light-emitting device that is opened.
FIG. 11B illustrates the light-emitting device that is being opened
or being folded. FIG. 11C illustrates the light-emitting device
that is folded. FIG. 12A is a side view of the light-emitting
device in the state shown in FIG. 11C. FIG. 12B is a top view of
the light-emitting device in the state shown in FIG. 11A.
[0177] As illustrated in FIG. 11A, FIG. 12B, and the like, the
support 103a(1) may overlap with the connection portion 105a or the
spacers 108. At this time, the support 103a(1) is preferably formed
using a material that blocks visible light in order that the
connection portion 105a or the spacers 108 can be prevented from
being seen by a user viewing the light-emitting surface of the
light-emitting device. Note that a light-blocking layer may be
provided as described in Modification Example 1.
[0178] In the structure where the support 103a(1) and the support
103a(2) are in contact with each other when the light-emitting
device is opened as illustrated in FIG. 11A, FIG. 12B, and the
like, the first region 161 cannot be bent inwardly. In this manner,
the direction in which a region with high flexibility is bent in
the light-emitting device can be controlled by the structure of the
support.
[0179] Furthermore, as illustrated in FIG. 12A, it is preferable
that a pair of regions with low flexibility positioned on the outer
side among the regions with low flexibility that overlap with one
another when the light-emitting device is folded be parallel to the
support plane of the light-emitting device, and that a region with
low flexibility positioned on the inner side not be parallel to the
support plane. In that case, the light-emitting device can be made
thinner.
MODIFICATION EXAMPLE 4
[0180] FIG. 12C is a side view of a light-emitting device that is
folded. The light-emitting device illustrated in FIG. 12C is a
modification example of the light-emitting device illustrated in
FIG. 12A.
[0181] In the structure where the support 103b(2) and the support
103b(3) can keep a certain distance from each other as illustrated
in FIG. 12C by adjusting the thickness of the support 103a(2) or
the support 103a(3), the light-emitting panel 101 can be prevented
from being bent with too small a radius of curvature.
[0182] An example of a light-emitting device that can be folded
inwardly in two parts is described in Structure Example A,
Structure Example B, and the like; however, one embodiment of the
present invention is not limited thereto. As in Structure Example F
below, a light-emitting device that can be folded outwardly in two
parts is also one embodiment of the present invention.
STRUCTURE EXAMPLE F
[0183] FIG. 13A illustrates a light-emitting device that is opened.
FIG. 13B is a side view of the light-emitting device that is
folded.
[0184] The light-emitting device has a first region 171, a second
region 172, and a third region 173. The first region 171 is
positioned between the second region 172 and the third region 173.
The first region 171 has the highest flexibility of the three
regions.
[0185] The light-emitting device includes the light-emitting panel
101, the support 103a(1), the support 103a(2), the support 103b(1),
the support 103b(2), and the connection portion 105.
[0186] The support 103a(1) and the support 103a(2) are apart from
each other. The support 103b(1) and the support 103b(2) are apart
from each other. The four supports each have lower flexibility than
the light-emitting panel 101.
[0187] The first region 171 includes the light-emitting panel 101
and the connection portion 105. The light-emitting panel 101 and
the connection portion 105 overlap with each other.
[0188] The first region 171 is a portion at which the
light-emitting panel 101 can be bent outwardly. For the details,
the description of the connection portion 105a in Structure
[0189] Example D can be referred to. The light-emitting panel 101
may be bent inwardly at the first region 171.
[0190] In the second region 172, the light-emitting panel 101 is
provided between the support 103a(1) and the support 103b(1). In
the third region 173, the light-emitting panel 101 is provided
between the support 103a(2) and the support 103b(2).
MODIFICATION EXAMPLE 5
[0191] FIG. 13C is a side view of a light-emitting device that is
folded. The light-emitting device illustrated in FIG. 13C is a
modification example of the light-emitting device illustrated in
FIG. 13B.
[0192] The light-emitting device illustrated in FIG. 13C includes
one spacer 108. In the spacer 108, a plurality of cuts are
provided. A plurality of projections separated by the cuts function
like the plurality of spacers described in the above structure
examples. That is, when the first region 171 is bent, the angle
between normals of facing planes of the two adjacent projections
changes according to the bending of the light-emitting panel 101.
Accordingly, a neutral plane can be formed in the light-emitting
panel 101 or in the vicinity of the light-emitting panel 101. The
cuts are preferably formed deeply because a neutral plane can be
easily formed in the light-emitting panel 101 or in the vicinity of
the light-emitting panel 101. Note that two or more spacers 108
each having a cut may be provided.
[0193] As described above, in this embodiment, when a region with
high flexibility in a light-emitting device has the structure in
which a light-emitting panel and a member overlap with each other,
the mechanical strength of the region with high flexibility can be
improved. A neutral plane can be formed in the light-emitting panel
or in the vicinity of the light-emitting panel even when the member
is provided. As a result, the light-emitting panel does not easily
expand or contract even when the light-emitting device is bent, and
thus the light-emitting panel can be prevented from being
broken.
[0194] This embodiment can be combined with any of the other
embodiments as appropriate.
EMBODIMENT 2
[0195] In this embodiment, a light-emitting panel will be described
with reference to drawings.
[0196] Although a light-emitting panel mainly including an organic
EL element will be described in this embodiment as an example, one
embodiment of the present invention is not limited to this
example.
[0197] When the light-emitting panel described in this embodiment
is bent, the minimum radius of curvature of a bent portion of the
light-emitting panel can be greater than or equal to 1 mm and less
than or equal to 150 mm, greater than or equal to 1 mm and less
than or equal to 100 mm, greater than or equal to 1 mm and less
than or equal to 50 mm, greater than or equal to 1 mm and less than
or equal to 10 mm, or greater than or equal to 2 mm and less than
or equal to 5 mm. The light-emitting panel in this embodiment is
free from breakage of an element even when bent with a small radius
of curvature (e.g., greater than or equal to 2 mm and less than or
equal to 5 mm) and has high reliability. Bending the light-emitting
panel with a small radius of curvature can make the light-emitting
device of one embodiment of the present invention thin. There is no
limitation on the direction in which the light-emitting panel in
this embodiment is bent. Further, the number of bent portions may
be one or more than one.
SPECIFIC EXAMPLE 1
[0198] FIG. 14A is a plan view of a light-emitting panel, and FIG.
14B is an example of a cross-sectional view taken along
dashed-dotted line D1-D2 in FIG. 14A. The light-emitting panel in
Specific Example 1 is a top-emission light-emitting panel using a
color filter method. In this embodiment, the light-emitting panel
can have a structure in which subpixels of three colors of red (R),
green (G), and blue (B), for example, express one color; a
structure in which subpixels of four colors of R, G, B, and white
(W) express one color; a structure in which subpixels of four
colors of R, G, B, and yellow (Y) express one color; or the like.
There is no particular limitation on color elements, and colors
other than R, G, B, W, and Y may be used. For example, cyan or
magenta may be used.
[0199] The light-emitting panel illustrated in FIG. 14A includes a
light-emitting portion 804, a driver circuit portion 806, and an
FPC 808.
[0200] The light-emitting panel illustrated in FIG. 14B includes a
first flexible substrate 701, a first bonding layer 703, a first
insulating layer 705, a first functional layer (a plurality of
transistors, a conductive layer 857, an insulating layer 815, an
insulating layer 817, a plurality of light-emitting elements, and
an insulating layer 821), a third bonding layer 822, a second
functional layer (a coloring layer 845 and a light-blocking layer
847), a second insulating layer 715, a second bonding layer 713,
and a second flexible substrate 711. The third bonding layer 822,
the second insulating layer 715, the second bonding layer 713, and
the second flexible substrate 711 transmit visible light.
Light-emitting elements and transistors in the light-emitting
portion 804 and the driver circuit portion 806 are sealed with the
first flexible substrate 701, the second flexible substrate 711,
and the third bonding layer 822.
[0201] In the light-emitting portion 804, a transistor 820 and a
light-emitting element 830 are provided over the first flexible
substrate 701 with the first bonding layer 703 and the first
insulating layer 705 placed therebetween. The light-emitting
element 830 includes a lower electrode 831 over the insulating
layer 817, an EL layer 833 over the lower electrode 831, and an
upper electrode 835 over the EL layer 833. The lower electrode 831
is electrically connected to a source electrode or a drain
electrode of the transistor 820. An end portion of the lower
electrode 831 is covered with the insulating layer 821. The lower
electrode 831 preferably reflects visible light. The upper
electrode 835 transmits visible light.
[0202] In the light-emitting portion 804, the coloring layer 845
overlapping with the light-emitting element 830 and the
light-blocking layer 847 overlapping with the insulating layer 821
are provided. The space between the light-emitting element 830 and
the coloring layer 845 is filled with the third bonding layer
822.
[0203] The insulating layer 815 has an effect of preventing
diffusion of impurities into a semiconductor included in the
transistor. As the insulating layer 817, an insulating layer having
a planarization function is preferably used in order to reduce
surface unevenness due to the transistor.
[0204] In the driver circuit portion 806, a plurality of
transistors are provided over the first flexible substrate 701 with
the first bonding layer 703 and the first insulating layer 705
positioned therebetween. FIG. 14B illustrates one of the
transistors included in the driver circuit portion 806.
[0205] The first insulating layer 705 and the first flexible
substrate 701 are attached to each other with the first bonding
layer 703. The second insulating layer 715 and the second flexible
substrate 711 are attached to each other with the second bonding
layer 713. The first insulating layer 705 and the second insulating
layer 715 are preferably highly resistant to moisture, in which
case impurities such as water can be prevented from entering the
light-emitting element 830 or the transistor 820, leading to higher
reliability of the light-emitting panel.
[0206] The conductive layer 857 is electrically connected to an
external input terminal through which a signal or a potential from
the outside is transmitted to the driver circuit portion 806. Here,
an example in which the FPC 808 is provided as the external input
terminal is described. To prevent an increase in the number of
fabrication steps, the conductive layer 857 is preferably formed
using the same material and the same step as the electrode or the
wiring in the light-emitting portion or the driver circuit portion.
Here, an example is described in which the conductive layer 857 is
formed using the same material and the same step as the electrodes
of the transistor 820. [0183]
[0207] In the light-emitting panel in FIG. 14B, the FPC 808 is
positioned over the second flexible substrate 711. A connector 825
is connected to the conductive layer 857 through an opening
provided in the second flexible substrate 711, the second bonding
layer 713, the second insulating layer 715, the third bonding layer
822, the insulating layer 817, and the insulating layer 815.
Furthermore, the connector 825 is connected to the FPC 808. That
is, the FPC 808 and the conductive layer 857 are electrically
connected to each other through the connector 825. When the
conductive layer 857 and the second flexible substrate 711 overlap
with each other, an opening formed in the second flexible substrate
711 (or the use of a substrate with an opening) allows the
conductive layer 857, the connector 825, and the FPC 808 to be
electrically connected to each other.
[0208] A modification example of the light-emitting panel
illustrated in FIGS. 14A and 14B will be described. FIG. 15A is a
plan view of a light-emitting panel, and FIG. 15B is an example of
a cross-sectional view taken along dashed-dotted line D3-D4 in FIG.
15A. FIG. 16A is an example of a cross-sectional view taken along
dashed-dotted line D5-D6 in FIG. 15A.
[0209] The light-emitting panel illustrated in FIGS. 15A and 15B
shows an example in which the first flexible substrate 701 and the
second flexible substrate 711 have different sizes. The FPC 808 is
positioned over the second insulating layer 715 and does not
overlap with the second flexible substrate 711. The connector 825
is connected to the conductive layer 857 through an opening
provided in the second insulating layer 715, the third bonding
layer 822, the insulating layer 817, and the insulating layer 815.
There is no limitation on the material for the second flexible
substrate 711 because an opening does not need to be provided in
the second flexible substrate 711.
[0210] It is preferred that the insulating layer formed using an
organic resin having a poor gas barrier property and a poor
moisture-resistant property not be exposed in an end portion of the
light-emitting device. With such a structure, entry of impurities
from the side surface of the light-emitting device can be
prevented. For example, as illustrated in FIG. 15B and FIG. 16A,
the structure in which the insulating layer 817 is not provided in
the end portion of the light-emitting device may be employed.
[0211] FIG. 16B shows a modification example of the light-emitting
portion 804.
[0212] The light-emitting panel illustrated in FIG. 16B includes
insulating layers 817a and 817b and a conductive layer 856 over the
insulating layer 817a. The source electrode or the drain electrode
of the transistor 820 and the lower electrode of the light-emitting
element 830 are electrically connected to each other through the
conductive layer 856.
[0213] The light-emitting panel illustrated in FIG. 16B includes a
spacer 823 over the insulating layer 821. The spacer 823 can adjust
the distance between the first flexible substrate 701 and the
second flexible substrate 711.
[0214] The light-emitting panel in FIG. 16B includes an overcoat
849 covering the coloring layer 845 and the light-blocking layer
847. The space between the light-emitting element 830 and the
overcoat 849 is filled with the bonding layer 822.
[0215] FIG. 16C shows a modification example of the light-emitting
element 830.
[0216] Note that as illustrated in FIG. 16C, the light-emitting
element 830 may include an optical adjustment layer 832 between the
lower electrode 831 and the EL layer 833. A light-transmitting
conductive material is preferably used for the optical adjustment
layer 832. Owing to the combination of a color filter (the coloring
layer) and a microcavity structure (the optical adjustment layer),
light with high color purity can be extracted from the
light-emitting panel of one embodiment of the present invention.
The thickness of the optical adjustment layer may be varied
depending on the color of the subpixel.
SPECIFIC EXAMPLE 2
[0217] A light-emitting panel illustrated in FIG. 16D includes the
first flexible substrate 701, the first bonding layer 703, the
first insulating layer 705, a first functional layer (a conductive
layer 814, a conductive layer 857a, a conductive layer 857b, the
light-emitting element 830, and the insulating layer 821), the
second bonding layer 713, and the second flexible substrate
711.
[0218] The conductive layer 857a and the conductive layer 857b
serve as external connection electrodes of the light-emitting panel
and can each be electrically connected to an FPC or the like.
[0219] The light-emitting element 830 includes the lower electrode
831, the EL layer 833, and the upper electrode 835. An end portion
of the lower electrode 831 is covered with the insulating layer
821. The light-emitting element 830 has a bottom-emission
structure, a top-emission structure, or a dual-emission structure.
The electrode, substrate, insulating layer, and the like through
which light is extracted transmit visible light. The conductive
layer 814 is electrically connected to the lower electrode 831.
[0220] The substrate through which light is extracted may have, as
a light extraction structure, a hemispherical lens, a micro lens
array, a film provided with an uneven surface structure, a light
diffusing film, or the like. For example, the substrate with the
light extraction structure can be formed by bonding the above lens
or film to a resin substrate with an adhesive or the like having
substantially the same refractive index as the substrate, the lens,
or the film.
[0221] The conductive layer 814 is preferably, though not
necessarily, provided because voltage drop due to the resistance of
the lower electrode 831 can be inhibited. In addition, for a
similar purpose, a conductive layer electrically connected to the
upper electrode 835 may be provided over the insulating layer 821,
the EL layer 833, the upper electrode 835, or the like.
[0222] The conductive layer 814 can be a single layer or a stacked
layer formed using a material selected from copper, titanium,
tantalum, tungsten, molybdenum, chromium, neodymium, scandium,
nickel, and aluminum, an alloy material containing any of these
materials as its main component, and the like. The thickness of the
conductive layer 814 can be, for example, greater than or equal to
0.1 .mu.m and less than or equal to 3 .mu.m, preferably greater
than or equal to 0.1 .mu.m and less than or equal to 0.5 .mu.m.
SPECIFIC EXAMPLE 3
[0223] FIG. 15A is a plan view of a light-emitting panel. FIG. 17A
is an example of a cross-sectional view taken along dashed-dotted
line D3-D4 in FIG. 15A. The light-emitting panel in Specific
Example 3 is a bottom-emission light-emitting panel using a color
filter method.
[0224] The light-emitting panel illustrated in FIG. 17A includes
the first flexible substrate 701, the first bonding layer 703, the
first insulating layer 705, a first functional layer (a plurality
of transistors, the conductive layer 857, the insulating layer 815,
the coloring layer 845, the insulating layer 817a, the insulating
layer 817b, the conductive layer 856, a plurality of light-emitting
elements, and the insulating layer 821), the second bonding layer
713, and the second flexible substrate 711. The first flexible
substrate 701, the first bonding layer 703, the first insulating
layer 705, the insulating layer 815, the insulating layer 817a, and
the insulating layer 817b transmit visible light.
[0225] In the light-emitting portion 804, the transistor 820, a
transistor 824, and the light-emitting element 830 are provided
over the first flexible substrate 701 with the first bonding layer
703 and the first insulating layer 705 positioned therebetween. The
light-emitting element 830 includes the lower electrode 831 over
the insulating layer 817b, the EL layer 833 over the lower
electrode 831, and the upper electrode 835 over the EL layer 833.
The lower electrode 831 is electrically connected to the source
electrode or the drain electrode of the transistor 820. An end
portion of the lower electrode 831 is covered with the insulating
layer 821. The upper electrode 835 preferably reflects visible
light. The lower electrode 831 transmits visible light. There is no
particular limitation on the position of the coloring layer 845
overlapping with the light-emitting element 830; for example, the
coloring layer 845 may be provided between the insulating layer
817a and the insulating layer 817b or between the insulating layer
815 and the insulating layer 817a.
[0226] In the driver circuit portion 806, a plurality of
transistors are provided over the first flexible substrate 701 with
the first bonding layer 703 and the first insulating layer 705
positioned therebetween. FIG. 17A illustrates two of the
transistors in the driver circuit portion 806.
[0227] The first insulating layer 705 and the first flexible
substrate 701 are attached to each other with the first bonding
layer 703. The first insulating layer 705 is preferably highly
resistant to moisture, in which case impurities such as water can
be prevented from entering the light-emitting element 830, the
transistor 820, or the transistor 824, leading to higher
reliability of the light-emitting panel.
[0228] The conductive layer 857 is electrically connected to an
external input terminal through which a signal or a potential from
the outside is transmitted to the driver circuit portion 806. In
this example, the FPC 808 is provided as the external input
terminal, and the conductive layer 857 is formed using the same
material and the same step as the conductive layer 856.
SPECIFIC EXAMPLE 4
[0229] FIG. 15A is a plan view of a light-emitting panel. FIG. 17B
is an example of a cross-sectional view taken along dashed-dotted
line D3-D4 in FIG. 15A. The light-emitting panel in Specific
Example 4 is a top-emission light-emitting panel using a separate
coloring method.
[0230] The light-emitting panel in FIG. 17B includes the first
flexible substrate 701, the first bonding layer 703, the first
insulating layer 705, a first functional layer (a plurality of
transistors, the conductive layer 857, the insulating layer 815,
the insulating layer 817, a plurality of light-emitting elements,
the insulating layer 821, and the spacer 823), the second bonding
layer 713, and the second flexible substrate 711. The second
bonding layer 713 and the second flexible substrate 711 transmit
visible light.
[0231] In the light-emitting panel illustrated in FIG. 17B, the
connector 825 is positioned over the insulating layer 815. The
connector 825 is connected to the conductive layer 857 through an
opening provided in the insulating layer 815. The connector 825 is
also connected to the FPC 808. That is, the FPC 808 and the
conductive layer 857 are electrically connected to each other
through the connector 825.
EXAMPLES OF MATERIALS
[0232] Next, materials that can be used for the light-emitting
panel will be described. Note that description of the components
already described in this specification is omitted in some
cases.
[0233] the substrates, glass, quartz, an organic resin, a metal, an
alloy, or the like can be used. The substrate through which light
from the light-emitting element is extracted is formed using a
material that transmits the light.
[0234] It is particularly preferable to use a flexible substrate.
For example, it is possible to use glass, a metal, or an alloy that
is thin enough to have flexibility, or an organic resin. For
example, the thickness of the flexible substrate is preferably
greater than or equal to 1 .mu.m and less than or equal to 200
.mu.m, further preferably greater than or equal to 1 .mu.m and less
than or equal to 100 .mu.m, still further preferably greater than
or equal to 1 .mu.m and less than or equal to 50 .mu.m, and
particularly preferably greater than or equal to 1 .mu.m and less
than or equal to 25 .mu.m.
[0235] An organic resin, which has a smaller specific gravity than
glass, is preferably used for the flexible substrate, in which case
the light-emitting panel can be lighter in weight than that using
glass.
[0236] A material with high toughness is preferably used for the
substrates. In that case, a light-emitting panel with high impact
resistance that is less likely to be broken can be provided. For
example, when an organic resin substrate or a metal or alloy
substrate with a small thickness is used, the light-emitting panel
can be lightweight and less likely to be broken as compared with
the case where a glass substrate is used.
[0237] A metal material and an alloy material, which have high
thermal conductivity, are preferred because they can easily conduct
heat to the whole substrate and accordingly can prevent a local
temperature rise in the light-emitting panel. The thickness of a
substrate using a metal material or an alloy material is preferably
greater than or equal to 10 .mu.m and less than or equal to 200
.mu.m, further preferably greater than or equal to 20 .mu.m and
less than or equal to 50 .mu.m.
[0238] Although there is no particular limitation on a material for
the metal substrate and the alloy substrate, it is preferable to
use, for example, aluminum, copper, nickel, or a metal alloy such
as an aluminum alloy or stainless steel.
[0239] Furthermore, when a material with high thermal emissivity is
used for the substrate, the surface temperature of the
light-emitting panel can be prevented from rising, leading to
prevention of breakage or a decrease in reliability of the
light-emitting panel. For example, the substrate may have a
stacked-layer structure of a metal substrate and a layer with high
thermal emissivity (e.g., a layer formed using a metal oxide or a
ceramic material).
[0240] Examples of a material having flexibility and a
light-transmitting property include polyester resins such as
polyethylene terephthalate (PET) and polyethylene naphthalate
(PEN), a polyacrylonitrile resin, a polyimide resin, a polymethyl
methacrylate resin, a polycarbonate (PC) resin, a polyethersulfone
(PES) resin, a polyamide resin (e.g., nylon or aramid), a
cycloolefin resin, a polystyrene resin, a polyamide imide resin, a
polyvinyl chloride resin, and a polytetrafluoroethylene (PTFE)
resin. In particular, a material with a low coefficient of linear
expansion is preferred, and for example, a polyamide imide resin, a
polyimide resin, a polyamide resin, or PET can be suitably used. It
is also possible to use a substrate in which a fibrous body is
impregnated with a resin (also referred to as prepreg) or a
substrate whose coefficient of linear expansion is reduced by
mixing an organic resin with an inorganic filler.
[0241] The flexible substrate may have a stacked-layer structure of
a layer of any of the above-mentioned materials and a hard coat
layer by which a surface of the device is protected from damage
(e.g., a silicon nitride layer), a layer that can disperse pressure
(e.g., an aramid resin layer), or the like.
[0242] The flexible substrate may be formed by stacking a plurality
of layers. When a glass layer is used, a barrier property against
water and oxygen can be improved and thus a reliable light-emitting
panel can be provided.
[0243] For example, it is possible to use a flexible substrate in
which a glass layer, a bonding layer, and an organic resin layer
are stacked from the side closer to a light-emitting element. The
thickness of the glass layer is greater than or equal to 20 .mu.m
and less than or equal to 200 .mu.m, preferably greater than or
equal to 25 .mu.m and less than or equal to 100 .mu.m. With such a
thickness, the glass layer can have both high flexibility and a
high barrier property against water and oxygen. The thickness of
the organic resin layer is greater than or equal to 10 .mu.m and
less than or equal to 200 .mu.m, preferably greater than or equal
to 20 .mu.m and less than or equal to 50 .mu.m. Providing such an
organic resin layer outside the glass layer, occurrence of a crack
or a break in the glass layer can be suppressed and mechanical
strength can be improved. With the substrate using such a composite
material of a glass material and an organic resin, a flexible
light-emitting panel with high reliability can be provided.
[0244] For the bonding layer, various curable adhesives such as a
photo curable adhesive (e.g., an ultraviolet curable adhesive), a
reactive curable adhesive, a thermosetting adhesive, and an
anaerobic adhesive can be used. Examples of these adhesives include
an epoxy resin, an acrylic resin, a silicone resin, a phenol resin,
a polyimide resin, an imide resin, a polyvinyl chloride (PVC)
resin, a polyvinyl butyral (PVB) resin, and an ethylene vinyl
acetate (EVA) resin. A material with low moisture permeability,
such as an epoxy resin, is particularly preferred. Alternatively, a
two-component resin may be used. An adhesive sheet or the like may
be used.
[0245] Furthermore, the resin may include a drying agent. For
example, it is possible to use a substance that adsorbs moisture by
chemical adsorption, such as oxide of an alkaline earth metal
(e.g., calcium oxide or barium oxide). Alternatively, it is
possible to use a substance that adsorbs moisture by physical
adsorption, such as zeolite or silica gel. The drying agent is
preferably included because it can prevent impurities such as
moisture from entering the functional element, thereby improving
the reliability of the light-emitting panel.
[0246] When a filler with a high refractive index or a light
scattering member is mixed into the resin, the efficiency of light
extraction from the light-emitting element can be improved. For
example, titanium oxide, barium oxide, zeolite, or zirconium can be
used.
[0247] Insulating films highly resistant to moisture are preferably
used as the first insulating layer 705 and the second insulating
layer 715. Alternatively, the first insulating layer 705 and the
second insulating layer 715 preferably have a function of
preventing diffusion of impurities to the light-emitting
element.
[0248] Examples of the insulating film highly resistant to moisture
include a film containing nitrogen and silicon (e.g., a silicon
nitride film and a silicon nitride oxide film) and a film
containing nitrogen and aluminum (e.g., an aluminum nitride film).
Alternatively, a silicon oxide film, a silicon oxynitride film, an
aluminum oxide film, or the like may be used.
[0249] For example, the moisture vapor transmission rate of the
insulating film highly resistant to moisture is lower than or equal
to 1.times.10.sup.-5 [g/(m.sup.2day)], preferably lower than or
equal to 1.times.10.sup.-6 [g/(m.sup.2day)], further preferably
lower than or equal to 1.times.10.sup.-7 [g/(m.sup.2day)], still
further preferably lower than or equal to 1.times.10.sup.-8
[g/(m.sup.2day)].
[0250] In the light-emitting panel, it is necessary that at least
one of the first insulating layer 705 and the second insulating
layer 715 transmit light emitted from the light-emitting element.
One of the first insulating layer 705 and the second insulating
layer 715, which transmits light emitted from the light-emitting
element, preferably has higher average transmittance of light
having a wavelength greater than or equal to 400 nm and less than
or equal to 800 nm than the other.
[0251] There is no particular limitation on the structure of the
transistors in the light-emitting panel. For example, a forward
staggered transistor or an inverted staggered transistor may be
used. A top-gate transistor or a bottom-gate transistor may be
used. There is no particular limitation on a semiconductor material
used for the transistors, and silicon, germanium, or an organic
semiconductor can be used, for example. Alternatively, an oxide
semiconductor containing at least one of indium, gallium, and zinc
(e.g., In--Ga--Zn-based metal oxide) may be used.
[0252] There is no particular limitation on the crystallinity of a
semiconductor material used for the transistors, and an amorphous
semiconductor or a semiconductor having crystallinity (a
microcrystalline semiconductor, a polycrystalline semiconductor, a
single crystal semiconductor, or a semiconductor partly including
crystal regions) may be used. A semiconductor having crystallinity
is preferably used, in which case deterioration of the transistor
characteristics can be suppressed.
[0253] For stable characteristics of the transistor, a base film is
preferably provided. The base film can be formed with a
single-layer structure or a stacked-layer structure using an
inorganic insulating film such as a silicon oxide film, a silicon
nitride film, a silicon oxynitride film, or a silicon nitride oxide
film. The base film can be formed by a sputtering method, a
chemical vapor deposition (CVD) method (e.g., a plasma CVD method,
a thermal CVD method, or a metal organic CVD (MOCVD) method), an
atomic layer deposition (ALD) method, a coating method, a printing
method, or the like. Note that the base film is not necessarily
provided if not necessary. In each of the above structure examples,
the first insulating layer 705 can serve as a base film of the
transistor.
[0254] As the light-emitting element, a self-luminous element can
be used, and an element whose luminance is controlled by current or
voltage is included in the category of the light-emitting element.
For example, a light-emitting diode (LED), an organic EL element,
or an inorganic EL element can be used.
[0255] The light-emitting element can have any of a top-emission
structure, a bottom-emission structure, and a dual-emission
structure. A conductive film that transmits visible light is used
as the electrode through which light is extracted. A conductive
film that reflects visible light is preferably used as the
electrode through which light is not extracted.
[0256] The conductive film that transmits visible light can be
formed using, for example, indium oxide, indium tin oxide (ITO),
indium zinc oxide, zinc oxide (ZnO), or zinc oxide to which gallium
is added. It is also possible to use a film of a metal material
such as gold, silver, platinum, magnesium, nickel, tungsten,
chromium, molybdenum, iron, cobalt, copper, palladium, or titanium;
an alloy containing any of these metal materials; or a nitride of
any of these metal materials (e.g., titanium nitride) when the film
is thin enough to have a light-transmitting property.
Alternatively, a stack of any of the above materials can be used as
the conductive layer. For example, a stacked film of ITO and an
alloy of silver and magnesium is preferably used, in which case
conductivity can be increased. Further alternatively, graphene or
the like may be used.
[0257] For the conductive film that reflects visible light, a metal
material such as aluminum, gold, platinum, silver, nickel,
tungsten, chromium, molybdenum, iron, cobalt, copper, or palladium
or an alloy containing any of these metal materials can be used,
for example. Lanthanum, neodymium, germanium, or the like may be
added to the metal material or the alloy. Moreover, the conductive
film can be formed using an alloy containing aluminum (an aluminum
alloy) such as an alloy of aluminum and titanium, an alloy of
aluminum and nickel, an alloy of aluminum and neodymium, or an
alloy of aluminum, nickel, and lanthanum (Al--Ni--La), or an alloy
containing silver such as an alloy of silver and copper, an alloy
of silver, palladium, and copper (Ag--Pd--Cu, also referred to as
APC), or an alloy of silver and magnesium. An alloy of silver and
copper is preferable because of its high heat resistance. When a
metal film or a metal oxide film is stacked on an aluminum alloy
film, oxidation of the aluminum alloy film can be suppressed.
Examples of a material for the metal film or the metal oxide film
are titanium and titanium oxide. Alternatively, the conductive film
having a property of transmitting visible light and a film
containing any of the above metal materials may be stacked. For
example, it is possible to use a stacked film of silver and ITO or
a stacked film of an alloy of silver and magnesium and ITO.
[0258] Each of the electrodes can be formed by an evaporation
method or a sputtering method. Alternatively, a discharging method
such as an ink-jet method, a printing method such as a screen
printing method, or a plating method can be used.
[0259] When a voltage higher than the threshold voltage of the
light-emitting element is applied between the lower electrode 831
and the upper electrode 835, holes are injected to the EL layer 833
from the anode side and electrons are injected to the EL layer 833
from the cathode side. The injected electrons and holes are
recombined in the EL layer 833 and a light-emitting substance
contained in the EL layer 833 emits light.
[0260] The EL layer 833 includes at least a light-emitting layer.
In addition to the light-emitting layer, the EL layer 833 may
further include one or more layers containing any of a substance
with a high hole-injection property, a substance with a high
hole-transport property, a hole-blocking material, a substance with
a high electron-transport property, a substance with a high
electron-injection property, a substance with a bipolar property (a
substance with a high electron-transport property and a high
hole-transport property), and the like.
[0261] For the EL layer 833, either a low molecular compound or a
high molecular compound can be used, and an inorganic compound may
be used. Each of the layers included in the EL layer 833 can be
formed by any of the following methods: an evaporation method
(including a vacuum evaporation method), a transfer method, a
printing method, an ink-jet method, a coating method, and the
like.
[0262] The light-emitting element 830 may contain two or more kinds
of light-emitting substances. Thus, for example, a light-emitting
element that emits white light can be achieved. For example,
light-emitting substances are selected so that two or more
light-emitting substances emit complementary colors to obtain white
light emission. A light-emitting substance that emits red (R)
light, green (G) light, blue (B) light, yellow (Y) light, or orange
(0) light or a light-emitting substance that emits light containing
spectral components of two or more of R light, G light, and B light
can be used, for example. A light-emitting substance that emits
blue light and a light-emitting substance that emits yellow light
may be used, for example. At this time, the emission spectrum of
the light-emitting substance that emits yellow light preferably
contains spectral components of G light and R light. The emission
spectrum of the light-emitting element 830 preferably has two or
more peaks in the visible region (e.g., greater than or equal to
350 nm and less than or equal to 750 nm or greater than or equal to
400 nm and less than or equal to 800 nm).
[0263] The EL layer 833 may include a plurality of light-emitting
layers. In the EL layer 833, the plurality of light-emitting layers
may be stacked in contact with one another or may be stacked with a
separation layer provided therebetween. The separation layer may be
provided between a fluorescent layer and a phosphorescent layer,
for example.
[0264] The separation layer can be provided, for example, to
prevent energy transfer by the Dexter mechanism (particularly
triplet energy transfer) from a phosphorescent material in an
excited state which is generated in the phosphorescent layer to a
fluorescent material in the fluorescent layer. The thickness of the
separation layer may be several nanometers. Specifically, the
thickness of the separation layer may be greater than or equal to
0.1 nm and less than or equal to 20 nm, greater than or equal to 1
nm and less than or equal to 10 nm, or greater than or equal to 1
nm and less than or equal to 5 nm. The separation layer contains a
single material (preferably, a bipolar substance) or a plurality of
materials (preferably, a hole-transport material and an
electron-transport material).
[0265] The separation layer may be formed using a material
contained in the light-emitting layer in contact with the
separation layer. This facilitates the manufacture of the
light-emitting element and reduces the drive voltage. For example,
in the case where the phosphorescent layer contains a host
material, an assist material, and the phosphorescent material (a
guest material), the separation layer may contain the host material
and the assist material. In other words, the separation layer
includes a region not containing the phosphorescent material and
the phosphorescent layer includes a region containing the
phosphorescent material in the above structure. Thus, the
separation layer and the phosphorescent layer can be separately
deposited depending on the presence of the phosphorescent material.
With such a structure, the separation layer and the phosphorescent
layer can be formed in the same chamber. Thus, the manufacturing
cost can be reduced.
[0266] Moreover, the light-emitting element 830 may be a single
element including one EL layer or a tandem element in which EL
layers are stacked with a charge generation layer provided
therebetween.
[0267] The light-emitting element is preferably provided between a
pair of insulating films that are highly resistant to moisture, in
which case impurities such as water can be prevented from entering
the light-emitting element, thereby preventing a decrease in the
reliability of the light-emitting panel. Specifically, the use of
an insulating film highly resistant to moisture for the first
insulating layer 705 and the second insulating layer 715 allows the
light-emitting element to be located between a pair of insulating
films highly resistant to moisture, by which a decrease in the
reliability of the light-emitting panel can be prevented.
[0268] As the insulating layer 815, an inorganic insulating film
such as a silicon oxide film, a silicon oxynitride film, or an
aluminum oxide film can be used, for example. For the insulating
layers 817, 817a, and 817b, an organic material such as polyimide,
acrylic, polyamide, polyimide amide, or a benzocyclobutene-based
resin can be used, for example. Alternatively, a low dielectric
constant material (low-k material) or the like can be used.
Furthermore, each of the insulating layers may be formed by
stacking a plurality of insulating films.
[0269] The insulating layer 821 is formed using an organic
insulating material or an inorganic insulating material. As a
resin, a polyimide resin, a polyamide resin, an acrylic resin, a
siloxane resin, an epoxy resin, or a phenol resin can be used, for
example. It is particularly preferable that the insulating layer
821 be formed using a photosensitive resin material to have an
opening portion over the lower electrode 831 so that a sidewall of
the opening portion is formed as an inclined surface with
continuous curvature.
[0270] There is no particular limitation on the method for forming
the insulating layer 821. A photolithography method, a sputtering
method, an evaporation method, a droplet discharging method (e.g.,
an ink-jet method), a printing method (e.g., screen printing or
off-set printing), or the like may be used.
[0271] The spacer 823 can be formed using an inorganic insulating
material, an organic insulating material, a metal material, or the
like. As the inorganic insulating material and the organic
insulating material, a variety of materials that can be used for
the aforementioned insulating layers can be used, for example. As
the metal material, titanium, aluminum, or the like can be used.
When the spacer 823 containing a conductive material and the upper
electrode 835 are electrically connected to each other, a potential
drop due to the resistance of the upper electrode 835 can be
suppressed. The spacer 823 may have a tapered shape or an inverse
tapered shape.
[0272] A conductive layer functioning as an electrode of the
transistor, a wiring, an auxiliary wiring of the light-emitting
element, or the like in the light-emitting panel can be formed with
a single-layer structure or a stacked-layer structure using any of
metal materials such as molybdenum, titanium, chromium, tantalum,
tungsten, aluminum, copper, neodymium, and scandium and an alloy
material containing any of these elements, for example. The
conductive layer may be formed using a conductive metal oxide such
as indium oxide (e.g., In.sub.2O.sub.3), tin oxide (e.g.,
SnO.sub.2), ZnO, ITO, indium zinc oxide (e.g.,
In.sub.2O.sub.3-ZnO), or any of these metal oxide materials
containing silicon oxide.
[0273] The coloring layer is a colored layer that transmits light
in a specific wavelength range. For example, a color filter for
transmitting light in a red, green, blue, or yellow wavelength
range can be used. Each coloring layer is formed in a desired
position with any of various materials by a printing method, an
ink-jet method, an etching method using a photolithography method,
or the like. In a white subpixel, a resin such as a transparent
resin may be provided so as to overlap with the light-emitting
element.
[0274] The light-blocking layer is provided between adjacent
coloring layers. The light-blocking layer blocks light emitted from
an adjacent light-emitting element to prevent color mixture between
adjacent light-emitting elements. Here, the coloring layer is
provided such that its end portion overlaps with the light-blocking
layer, whereby light leakage can be reduced. For the light-blocking
layer, a material that blocks light from the light-emitting element
can be used; for example, a black matrix may be formed using a
metal material or a resin material containing pigment or dye. Note
that it is preferable to provide the light-blocking layer in a
region other than the light-emitting portion, such as a driver
circuit portion, in which case undesired leakage of guided light or
the like can be suppressed.
[0275] An overcoat covering the coloring layer and the
light-blocking layer may be provided. The overcoat can prevent
impurities and the like contained in the coloring layer from being
diffused into the light-emitting element. The overcoat is formed
with a material that transmits light emitted from the
light-emitting element; for example, it is possible to use an
inorganic insulating film such as a silicon nitride film or a
silicon oxide film, an organic insulating film such as an acrylic
film or a polyimide film, or a stacked layer of an organic
insulating film and an inorganic insulating film.
[0276] In the case where upper surfaces of the coloring layer and
the light-blocking layer are coated with a material of the bonding
layer, a material that has high wettability with respect to the
material of the bonding layer is preferably used as the material of
the overcoat. For example, the overcoat is preferably an oxide
conductive film such as an ITO film or a metal film such as an Ag
film that is thin enough to transmit light.
[0277] When the overcoat is formed using a material that has high
wettability with respect to the material for the bonding layer, the
material for the bonding layer can be uniformly applied. Thus,
entry of bubbles in the step of attaching the pair of substrates to
each other can be prevented, and thus a display defect can be
prevented.
[0278] For the connector, any of a variety of anisotropic
conductive films (ACF), anisotropic conductive pastes (ACP), and
the like can be used.
[0279] As described above, one embodiment of the present invention
can be applied to a light-emitting panel, a display panel, a touch
panel, and the like.
[0280] Examples of a display element include a light-emitting
element such as an organic EL element, an inorganic EL element, or
an LED, a liquid crystal element, an electrophoretic element, and a
display element using micro electro mechanical systems (MEMS).
[0281] Note that the light-emitting panel of one embodiment of the
present invention may be used as a display device or as a lighting
device. For example, it may be used as a light source such as a
backlight or a front light, that is, a lighting device for a
display panel.
[0282] This embodiment can be combined with any of the other
embodiments as appropriate.
Embodiment 3
[0283] In this embodiment, a touch panel will be described with
reference to drawings. Note that the above description can be
referred to for the components of a touch panel, which are similar
to those of the light-emitting panel described in Embodiment 2.
Although a touch panel including a light-emitting element is
described in this embodiment as an example, one embodiment of the
present invention is not limited to this example. For example, a
touch panel including another element (e.g., a display element),
the example of which is shown in Embodiment 2, is also one
embodiment of the present invention.
STRUCTURE EXAMPLE 1
[0284] FIG. 18A is a top view of the touch panel. FIG. 18B is a
cross-sectional view taken along dashed-dotted line A-B and
dashed-dotted line C-D in FIG. 18A. FIG. 18C is a cross-sectional
view taken along dashed-dotted line E-F in FIG. 18A.
[0285] A touch panel 390 illustrated in FIG. 18A includes a display
portion 301 (serving also as an input portion), a scan line driver
circuit 303g(1), an imaging pixel driver circuit 303g(2), an image
signal line driver circuit 303s(1), and an imaging signal line
driver circuit 303s(2).
[0286] The display portion 301 includes a plurality of pixels 302
and a plurality of imaging pixels 308.
[0287] The pixel 302 includes a plurality of subpixels. Each
subpixel includes a light-emitting element and a pixel circuit.
[0288] The pixel circuits can supply electric power for driving the
light-emitting element. The pixel circuits are electrically
connected to wirings through which selection signals are supplied.
The pixel circuits are also electrically connected to wirings
through which image signals are supplied.
[0289] The scan line driver circuit 303g(1) can supply selection
signals to the pixels 302.
[0290] The image signal line driver circuit 303s(1) can supply
image signals to the pixels 302.
[0291] A touch sensor can be formed using the imaging pixels 308.
Specifically, the imaging pixels 308 can sense a touch of a finger
or the like on the display portion 301.
[0292] The imaging pixels 308 include photoelectric conversion
elements and imaging pixel circuits.
[0293] The imaging pixel circuits can drive photoelectric
conversion elements. The imaging pixel circuits are electrically
connected to wirings through which control signals are
supplied.
[0294] The imaging pixel circuits are also electrically connected
to wirings through which power supply potentials are supplied.
[0295] Examples of the control signal include a signal for
selecting an imaging pixel circuit from which a recorded imaging
signal is read, a signal for initializing an imaging pixel circuit,
and a signal for determining the time it takes for an imaging pixel
circuit to sense light.
[0296] The imaging pixel driver circuit 303g(2) can supply control
signals to the imaging pixels 308.
[0297] The imaging signal line driver circuit 303s(2) can read out
imaging signals.
[0298] As illustrated in FIGS. 18B and 18C, the touch panel 390
includes the first flexible substrate 701, the first bonding layer
703, the first insulating layer 705, the second flexible substrate
711, the second bonding layer 713, and the second insulating layer
715. The first flexible substrate 701 and the second flexible
substrate 711 are bonded to each other with a third bonding layer
360.
[0299] The first flexible substrate 701 and the first insulating
layer 705 are attached to each other with the first bonding layer
703. The second flexible substrate 711 and the second insulating
layer 715 are attached to each other with the second bonding layer
713. Embodiment 2 can be referred to for materials used for the
substrates, the bonding layers, and the insulating layers.
[0300] Each of the pixels 302 includes a subpixel 302R, a subpixel
302G, and a subpixel 302B (see FIG. 18C).
[0301] For example, the subpixel 302R includes a light-emitting
element 350R and the pixel circuit. The pixel circuit includes a
transistor 302t that can supply electric power to the
light-emitting element 350R. Furthermore, the subpixel 302R
includes the light-emitting element 350R and an optical element
(e.g., a coloring layer 367R that transmits red light).
[0302] The light-emitting element 350R includes a lower electrode
351R, an EL layer 353, and an upper electrode 352, which are
stacked in this order (see FIG. 18C).
[0303] The EL layer 353 includes a first EL layer 353a, an
intermediate layer 354, and a second EL layer 353b, which are
stacked in this order.
[0304] Note that a microcavity structure can be provided for the
light-emitting element 350R so that light with a specific
wavelength can be efficiently extracted. Specifically, an EL layer
may be provided between a film that reflects visible light and a
film that partly reflects and partly transmits visible light, which
are provided so that light with a specific wavelength can be
efficiently extracted.
[0305] The subpixel 302R includes the third bonding layer 360 that
is in contact with the light-emitting element 350R and the coloring
layer 367R. The coloring layer 367R is positioned in a region
overlapping with the light-emitting element 350R. Accordingly, part
of light emitted from the light-emitting element 350R passes
through the third bonding layer 360 and through the coloring layer
367R and is emitted to the outside of the subpixel 302R as
indicated by an arrow in FIG. 18B or 18C.
[0306] The touch panel 390 includes a light-blocking layer 367BM.
The light-blocking layer 367BM is provided so as to surround the
coloring layer (e.g., the coloring layer 367R).
[0307] The touch panel 390 includes an anti-reflective layer 367p
positioned in a region overlapping with the display portion 301. As
the anti-reflective layer 367p, a circular polarizing plate can be
used, for example.
[0308] The touch panel 390 includes an insulating layer 321. The
insulating layer 321 covers the transistor 302t and the like. Note
that the insulating layer 321 can be used as a layer for
planarizing unevenness caused by the pixel circuits and the imaging
pixel circuits. An insulating layer that can inhibit diffusion of
impurities to the transistor 302t and the like can be used as the
insulating layer 321.
[0309] The touch panel 390 includes a partition 328 that overlaps
with an end portion of the lower electrode 351R. A spacer 329 that
controls the distance between the first flexible substrate 701 and
the second flexible substrate 711 is provided on the partition
328.
[0310] The image signal line driver circuit 303s(1) includes a
transistor 303t and a capacitor 303c. Note that the driver circuit
can be formed in the same process and over the same substrate as
the pixel circuits. As illustrated in FIG. 18B, the transistor 303t
may include a second gate 304 over the insulating layer 321. The
second gate 304 may be electrically connected to a gate of the
transistor 303t, or different potentials may be supplied to these
gates. Alternatively, if necessary, the second gate 304 may be
provided for the transistor 308t, the transistor 302t, or the
like.
[0311] The imaging pixels 308 each include a photoelectric
conversion element 308pand an imaging pixel circuit. The imaging
pixel circuit can sense light received by the photoelectric
conversion element 308p. The imaging pixel circuit includes the
transistor 308t. For example, a PIN photodiode can be used as the
photoelectric conversion element 308p.
[0312] The touch panel 390 includes a wiring 311 through which a
signal is supplied. The wiring 311 is provided with a terminal 319.
Note that an FPC 309 through which a signal such as an image signal
or a synchronization signal is supplied is electrically connected
to the terminal 319. Note that a printed wiring board (PWB) may be
attached to the FPC 309.
[0313] Note that transistors such as the transistors 302t, 303t,
and 308t can be formed in the same process. Alternatively, the
transistors may be formed in different processes.
STRUCTURE EXAMPLE 2
[0314] FIGS. 19A and 19B are perspective views of a touch panel
505. Note that FIGS. 19A and 19B illustrate only main components
for simplicity. FIGS. 20A and 20B are each a cross-sectional view
taken along dashed-dotted line X1-X2 in FIG. 19A.
[0315] As illustrated in FIGS. 19A and 19B, the touch panel 505
includes a display portion 501, the scan line driver circuit
303g(1), a touch sensor 595, and the like. Furthermore, the touch
panel 505 includes the first flexible substrate 701, the second
flexible substrate 711, and a flexible substrate 590.
[0316] The touch panel 505 includes a plurality of pixels and a
plurality of wirings 311. The plurality of wirings 311 can supply
signals to the pixels. The plurality of wirings 311 are arranged to
a peripheral portion of the first flexible substrate 701, and part
of the plurality of wirings 311 form the terminal 319. The terminal
319 is electrically connected to an FPC 509(1).
[0317] The touch panel 505 includes the touch sensor 595 and a
plurality of wirings 598. The plurality of wirings 598 are
electrically connected to the touch sensor 595. The plurality of
wirings 598 are arranged to a peripheral portion of the flexible
substrate 590, and part of the plurality of wirings 598 form a
terminal. The terminal is electrically connected to an FPC 509(2).
Note that in FIG. 19B, electrodes, wirings, and the like of the
touch sensor 595 provided on the back side of the flexible
substrate 590 (the side facing the first flexible substrate 701)
are indicated by solid lines for clarity.
[0318] As the touch sensor 595, for example, a capacitive touch
sensor can be used. Examples of the capacitive touch sensor are a
surface capacitive touch sensor and a projected capacitive touch
sensor. An example of using a projected capacitive touch sensor is
described here.
[0319] Examples of a projected capacitive touch sensor are a
self-capacitive touch sensor and a mutual capacitive touch sensor.
The use of a mutual capacitive type is preferable because multiple
points can be sensed simultaneously.
[0320] Note that a variety of sensors that can sense the closeness
or the contact of a sensing target such as a finger can be used as
the touch sensor 595.
[0321] The projected capacitive touch sensor 595 includes
electrodes 591 and electrodes 592. The electrodes 591 are
electrically connected to any of the plurality of wirings 598, and
the electrodes 592 are electrically connected to any of the other
wirings 598.
[0322] The electrodes 592 each have a shape of a plurality of
quadrangles arranged in one direction with one corner of a
quadrangle connected to one corner of another quadrangle as
illustrated in FIGS. 19A and 19B.
[0323] The electrodes 591 each have a quadrangular shape and are
arranged in a direction intersecting with the direction in which
the electrodes 592 extend. Note that the plurality of electrodes
591 are not necessarily arranged in the direction orthogonal to one
electrode 592 and may be arranged to intersect with one electrode
592 at an angle of less than 90 degrees.
[0324] The wiring 594 intersects with the electrode 592. The wiring
594 electrically connects two electrodes 591 between which one of
the electrodes 592 is positioned. The intersecting area of the
electrode 592 and the wiring 594 is preferably as small as
possible. Such a structure allows a reduction in the area of a
region where the electrodes are not provided, reducing unevenness
in transmittance. As a result, unevenness in luminance of light
from the touch sensor 595 can be reduced.
[0325] Note that the shapes of the electrodes 591 and the
electrodes 592 are not limited to the above-mentioned shapes and
can be any of a variety of shapes.
[0326] As illustrated in FIG. 20A, the touch panel 505 includes the
first flexible substrate 701, the first bonding layer 703, the
first insulating layer 705, the second flexible substrate 711, the
second bonding layer 713, and the second insulating layer 715. The
first flexible substrate 701 and the second flexible substrate 711
are attached to each other with the third bonding layer 360.
[0327] A bonding layer 597 attaches the flexible substrate 590 to
the second flexible substrate 711 so that the touch sensor 595
overlaps with the display portion 501. The bonding layer 597 has a
light-transmitting property.
[0328] The electrodes 591 and the electrodes 592 are formed using a
light-transmitting conductive material. As a light-transmitting
conductive material, a conductive oxide such as indium oxide,
indium tin oxide, indium zinc oxide, zinc oxide, or zinc oxide to
which gallium is added can be used. Note that a film including
graphene may be used as well. The film including graphene can be
formed, for example, by reducing a film including graphene oxide.
As a reducing method, a method with application of heat or the like
can be employed.
[0329] Note that as a material of the conductive films such as the
electrodes 591, the electrodes 592, and the wiring 594, that is,
wirings and electrodes forming the touch panel, a transparent
conductive film including indium oxide, tin oxide, zinc oxide, or
the like (e.g., ITO) can be given. A low-resistance material is
preferably used as a material that can be used as the wirings and
electrodes forming the touch panel. For example, silver, copper,
aluminum, a carbon nanotube, graphene, or a metal halide (such as a
silver halide) may be used. Alternatively, a metal nanowire
including a number of conductors with an extremely small width (for
example, a diameter of several nanometers) may be used. Further
alternatively, a net-like metal mesh with a conductor may be used.
For example, an Ag nanowire, a Cu nanowire, an Al nanowire, an Ag
mesh, a Cu mesh, or an Al mesh may be used. For example, in the
case of using an Ag nanowire as the wirings and electrodes forming
the touch panel, a visible light transmittance of 89% or more and a
sheet resistance of 40 ohm/square or more and 100 ohm/square or
less can be achieved. Since the above-described metal nanowire,
metal mesh, carbon nanotube, graphene, and the like, which are
examples of the material that can be used as the wirings and
electrodes forming the touch panel, have high visible light
transmittances, they may be used as electrodes of display elements
(e.g., a pixel electrode or a common electrode).
[0330] The electrodes 591 and the electrodes 592 may be formed by
depositing a light-transmitting conductive material on the flexible
substrate 590 by a sputtering method and then removing an
unnecessary portion by any of various patterning techniques such as
photolithography.
[0331] The electrodes 591 and the electrodes 592 are covered with
an insulating layer 593. Furthermore, openings reaching the
electrodes 591 are formed in the insulating layer 593, and the
wiring 594 electrically connects the adjacent electrodes 591. A
light-transmitting conductive material can be favorably used for
the wiring 594 because the aperture ratio of the touch panel can be
increased. Moreover, a material with higher conductivity than the
conductivities of the electrodes 591 and the electrodes 592 can be
favorably used for the wiring 594 because electric resistance can
be reduced.
[0332] Note that an insulating layer covering the insulating layer
593 and the wiring 594 may be provided to protect the touch sensor
595.
[0333] Furthermore, a connection layer 599 electrically connects
the wirings 598 to the FPC 509(2).
[0334] The display portion 501 includes a plurality of pixels
arranged in a matrix. Each pixel has the same structure as
Structure Example 1; thus, description is omitted.
[0335] As illustrated in FIG. 20B, the touch panel may include two
substrates of the first flexible substrate 701 and the second
flexible substrate 711 without including the flexible substrate
590. The second flexible substrate 711 and the second insulating
layer 715 are attached to each other with the second bonding layer
713, and the touch sensor 595 is provided in contact with the
second insulating layer 715. The coloring layer 367R and the
light-blocking layer 367BM are provided in contact with the
insulating layer 589 that covers the touch sensor 595. The
insulating layer 589 is not necessarily provided, in which case the
coloring layer 367R and the light-blocking layer 367BM are provided
in contact with the wiring 594.
STRUCTURE EXAMPLE 3
[0336] FIGS. 21A to 21C are cross-sectional views of a touch panel
505B. The touch panel 505B described in this embodiment is
different from the touch panel 505 in Structure Example 2 in that
received image data is displayed on the side where the transistors
are provided and that the touch sensor is provided on the first
flexible substrate 701 side of the display portion. Different
structures will be described in detail below, and the above
description is referred to for the other similar structures.
[0337] The coloring layer 367R is positioned in a region
overlapping with the light-emitting element 350R. The
light-emitting element 350R illustrated in FIG. 21A emits light to
the side where the transistor 302t is provided. Accordingly, part
of light emitted from the light-emitting element 350R passes
through the coloring layer 367R and is emitted to the outside of
the touch panel 505B as indicated by an arrow in FIG. 21A.
[0338] The touch panel 505B includes the light-blocking layer 367BM
on the light extraction side. The light-blocking layer 367BM is
provided so as to surround the coloring layer (e.g., the coloring
layer 367R).
[0339] The touch sensor 595 is provided not on the second flexible
substrate 711 side but on the first flexible substrate 701 side
(see FIG. 21A).
[0340] The bonding layer 597 attaches the flexible substrate 590 to
the first flexible substrate 701 so that the touch sensor 595
overlaps with the display portion. The bonding layer 597 has a
light-transmitting property.
[0341] Note that a structure in the case of using bottom-gate
transistors in the display portion 501 is illustrated in FIGS. 21A
and 21B.
[0342] For example, a semiconductor layer containing an oxide
semiconductor, amorphous silicon, or the like can be used in the
transistor 302t and the transistor 303t illustrated in FIG.
21A.
[0343] For example, a semiconductor layer containing
polycrystalline silicon or the like can be used in the transistor
302t and the transistor 303t illustrated in FIG. 21B.
[0344] A structure in the case of using top-gate transistors is
illustrated in FIG. 21C.
[0345] For example, a semiconductor layer containing
polycrystalline silicon, a single crystal silicon film that is
transferred from a single crystal silicon substrate, or the like
can be used in the transistor 302t and the transistor 303t
illustrated in FIG. 21C.
[0346] This embodiment can be combined with any of the other
embodiments as appropriate.
EXAMPLE 1
[0347] In this example, light-emitting devices of one embodiment of
the present invention were fabricated.
[0348] In this example, the light-emitting devices corresponding to
Structure Example B (see FIG. 2A and the like) and Structure
Example D (see FIG. 9A and the like), respectively, were
fabricated.
[0349] Light-emitting panels of this example were fabricated in the
following manner: a separation layer (tungsten film) was formed
over each of a pair of formation substrates (glass substrates);
layers to be separated (one of them included a transistor, a
light-emitting element, and the like, and the other included a
color filter and the like) were formed over the respective
separation layers; the pair of formation substrates was separated
from the layers to be separated; and then flexible substrates were
attached to the layers to be separated with an adhesive.
[0350] As the transistor, a transistor including a c-axis aligned
crystalline oxide semiconductor (CAAC-OS) was used. Unlike
amorphous semiconductor, the CAAC-OS has few defect states, so that
the reliability of the transistor can be improved. Moreover, since
the CAAC-OS does not have a grain boundary, a stable and uniform
film can be formed over a large area, and stress that is caused by
bending a flexible light-emitting device does not easily make a
crack in a CAAC-OS film.
[0351] A CAAC-OS is a crystalline oxide semiconductor having c-axis
alignment of crystals in a direction substantially perpendicular to
the film surface. It has been found that oxide semiconductors have
a variety of crystal structures other than a single crystal
structure. An example of such structures is a nano-crystal (nc)
structure, which is an aggregate of nanoscale microcrystals. The
crystallinity of a CAAC-OS structure is lower than that of a single
crystal structure and higher than that of an nc structure.
[0352] In this example, a channel-etched transistor including an
In--Ga--Zn-based oxide was used. The transistor was fabricated over
a glass substrate at a process temperature lower than 500 .degree.
C.
[0353] In a method of fabricating an element such as a transistor
directly on an organic resin such as a plastic substrate, the
temperature of the process for fabricating the element needs to be
lower than the upper temperature limit of the organic resin. In
this example, the formation substrate is a glass substrate and the
peeling layer, which is an inorganic film, has high heat
resistance; thus, the transistor can be fabricated at a temperature
equal to that when a transistor is fabricated over a glass
substrate. Thus, the performance and reliability of the transistor
can be easily secured.
[0354] As the light-emitting element, a tandem (stacked-layer)
organic EL element emitting white light was used. The
light-emitting element has a top emission structure. Light from the
light-emitting element is extracted outside through a color
filter.
[0355] The light-emitting panels of two kinds were fabricated.
[0356] FIGS. 22A to 22C show the light-emitting device
corresponding to Structure Example B. FIG. 22A illustrates the
light-emitting device that is opened. FIG. 22B illustrates the
light-emitting device that is being opened or being folded. FIG.
22C illustrates the light-emitting device that is folded.
[0357] The light-emitting device illustrated in FIGS. 22A to 22C
includes a magnet-type fixing unit as the fixing unit 107. The
connection portion 105 includes an elastic body and a plurality of
spacers. The light-blocking layer 109 is positioned so as to
overlap with the connection portion 105, whereby the connection
portion 105 can be prevented from being seen by a user viewing a
light-emitting surface of the light-emitting device.
[0358] In the light-emitting panel of the light-emitting device
illustrated in FIGS. 22A to 22C, a light-emitting portion (also
referred to as light-emitting region or pixel portion) has a size
of 5.9 inches diagonal, 720.times.1280 pixels, a pixel size of 102
.mu.m.times.102 .mu.m, a resolution of 249 ppi, and an aperture
ratio of 45.2%. A built-in scan driver and an external source
driver attached by chip on film (COF) were used. The frame
frequency was 60 Hz. Note that the light-emitting panel has a
weight of approximately 3 g and a thickness less than 100
.mu.m.
[0359] FIGS. 23A to 23C show the light-emitting device
corresponding to Structure Example D. FIG. 23A illustrates the
light-emitting device that is opened. FIG. 23B illustrates the
light-emitting device that is being opened or being folded. FIG.
23C illustrates the light-emitting device that is folded.
[0360] In the light-emitting panel of the light-emitting device
illustrated in FIGS. 23A to 23C, a light-emitting portion has a
size of 8.7 inches diagonal, 1080.times.1920 pixels, a pixel size
of 100 .mu.m.times.100 .mu.m, a resolution of 254 ppi, and an
aperture ratio of 46.0%. A built-in scan driver and an external
source driver attached by COF were used. The frame frequency was 60
Hz. Note that a capacitive touch sensor is incorporated in the
light-emitting panel. Note that the light-emitting panel has a
weight of approximately 6 g and a thickness less than 100
.mu.m.
[0361] As described above, by application of one embodiment of the
present invention, a light-emitting device that is highly portable
in a folded state and is highly browsable in an opened state
because of a seamless large light-emitting region was fabricated.
Furthermore, a light-emitting device in which a light-emitting
panel is prevented from being broken owing to folding was
fabricated.
REFERENCE NUMERALS
[0362] 101: light-emitting panel, 103: support, 103a: support,
103b: support, 105: connection portion, 105a: connection portion,
105b: connection portion, 106: elastic body, 107: fixing unit, 108:
spacer, 109: light-blocking layer, 111: light-emitting region, 112:
non-light-emitting region, 113a: protective layer, 113b: protective
layer, 151: first region, 152: second region, 153: third region,
161: first region, 162: second region, 163: third region, 164:
fourth region, 165: fifth region, 171: first region, 172: second
region, 173: third region, 301: display portion, 302: pixel, 302B:
subpixel, 302G: subpixel, 302R: subpixel, 302t: transistor, 303c:
capacitor, 303g(1): scan line driver circuit, 303g(2): imaging
pixel driver circuit, 303s(1): image signal line driver circuit,
303s(2): imaging signal line driver circuit, 303t: transistor, 304:
gate, 308: imaging pixel, 308p: photoelectric conversion element,
308t: transistor, 309: FPC, 311: wiring, 319: terminal, 321:
insulating layer, 328: partition, 329: spacer, 350R: light-emitting
element, 351R: lower electrode, 352: upper electrode, 353: EL
layer, 353a: EL layer, 353b: EL layer, 354: intermediate layer,
360: bonding layer, 367BM: light-blocking layer, 367p:
anti-reflective layer, 367R: coloring layer, 390: touch panel, 501:
display portion, 505: touch panel, 505B: touch panel, 509: FPC,
589: insulating layer, 590: flexible substrate, 591: electrode,
592: electrode, 593: insulating layer, 594: wiring, 595: touch
sensor, 597: bonding layer, 598: wiring, 599: connection layer,
701: flexible substrate, 703: bonding layer, 705: insulating layer,
711: flexible substrate, 713: bonding layer, 715: insulating layer,
804: light-emitting portion, 806: driver circuit portion, 808: FPC,
814: conductive layer, 815: insulating layer, 817: insulating
layer, 817a: insulating layer, 817b: insulating layer, 820:
transistor, 821: insulating layer, 822: bonding layer, 823: spacer,
824: transistor, 825: connector, 830: light-emitting element, 831:
lower electrode, 832: optical adjustment layer, 833: EL layer, 835:
upper electrode, 845: coloring layer, 847: light-blocking layer,
849: overcoat, 856: conductive layer, 857: conductive layer, 857a:
conductive layer, and 857b: conductive layer
[0363] This application is based on Japanese Patent Application
serial no. 2014-219135 filed with Japan Patent Office on Oct. 28,
2014, the entire contents of which are hereby incorporated by
reference.
* * * * *